Acta Universitatis Agriculturae Sueciae
Doctoral Thesis No. 2017:91
Faculty of Landscape Architecture, Horticulture
and Crop Production Science
Sound in Landscape Architecture
A Soundscape Approach to Noise
Gunnar Cerwén
Sound in Landscape Architecture
A Soundscape Approach to Noise
Gunnar Cerwén
Faculty of Landscape Architecture, Horticulture and Crop Production Science,
Department of Landscape Architecture, Planning and Management,
Alnarp
Doctoral Thesis
Swedish University of Agricultural Sciences
Alnarp 2017
Acta Universitatis agriculturae Sueciae
2017:91
Cover: 3D sketch depicting an urban soundscape intervention that was built and
studied as part of this thesis (Paper III). The schematic colour circles represent
traffic sounds (red) and forest sounds (green). The traffic sounds were screened by
the arbour intervention and the forest sounds were generated by speakers to
produce an additional masking effect.
(Image rendered by: Gunnar Cerwén)
ISSN 1652-6880
ISBN (print version) 978-91-7760-072-5
ISBN (electronic version) 978-91-7760-073-2
© 2017 Gunnar Cerwén, Alnarp
Print: SLU Repro, Alnarp 2017
Sound in Landscape Architecture
A Soundscape Approach to Noise
Abstract
Landscape planning and design involve decisions that have far-reaching effects,
positive and negative, on the soundscape. However, landscape architecture and related
disciplines have not fully recognised the possibilities of considering sound issues in
design projects. This is problematic, considering that sound influences health and
wellbeing and is an important factor in environmental experience.
This thesis examines how soundscape thinking can be facilitated in landscape
architecture. The work is based on a mixed-method approach and it is practiceorientated in the sense that it studies how landscape architects currently work with
sound and how they could work with sound in the future. The soundscape concept is
used to emphasise the experiential characteristics of the sonic environment and to
discuss the role of sound in landscape architecture, particularly in noise-exposed
situations. Applications of soundscape design are raised in several examples, including
construction of a design intervention as a reference project involving noise masking.
The understandings obtained are used to formulate a set of strategies and tools for
the profession as a soundscape approach to noise, in which problems and possibilities
are given consideration to ensure a varied and purposeful environment. A model based
on three categories is presented to evaluate and facilitate such a comprehensive
approach, where each of the three categories (localisation of functions, reduction of
unwanted sounds and introduction of wanted sounds) represents a central consideration
that can be taken in landscape architecture.
An extended version of the comprehensive model is also presented. It comprises a
list of 23 ‘soundscape actions’, each of which represents a concrete, general strategy
that can be adopted to improve soundscapes, particularly focusing on noise-exposed
situations. To increase applicability, the soundscape actions were developed in
collaboration with professional landscape architects, Master’s students, acousticians,
artists and other experts.
The findings are discussed in relation to contemporary challenges in the profession,
particularly focusing on the sustainability discourse and covering issues such as green
structures, densification and the notion of ‘quiet areas’.
Keywords: soundscape design, landscape architecture, acoustic environment, noise,
informational masking, urban design, quiet areas, sustainable development
Author’s address: Gunnar Cerwén, SLU, Department of Landscape Architecture,
Planning and Management, P.O. Box 58, 230 53 Alnarp, Sweden.
E-mail:
[email protected]
Preface
This thesis is a result of several years of exploration at the intersection between
landscape architecture and sound, particularly in practice-orientated situations
and through empirical studies. I have been interested in the topic ever since my
time as a student in landscape architecture.
In 2009, I produced a Master’s thesis investigating the relationship between
speaker sounds and outdoor environments. Following that work, I have
continued to explore sound in landscape architecture, gradually becoming more
interested in landscape architecture as a cultural practice and how soundscape
thinking can be given more focus in design solutions.
My own interest in the sound environment grew out of music and this
seems to be a path I share with many researchers in soundscape. For me, it was
experimental psychedelic garage rock music that would first stir a deeper
interest in sound. After many years of playing and recording music, I gradually
started to become more interested in related fields, such as psychoacoustics,
recording techniques, atmospheres and soundscapes.
As a landscape architect, I had a brief period of professional experience,
particularly working at design scale on projects such as playgrounds, parks,
private gardens and art installations. In addition to landscape architecture, I
also have academic training in fields that are specifically orientated towards
sound, such as music theory, music psychology, sound art and film sound. My
qualitative understanding of sound was the starting point and driving force for
the present thesis. This perspective was applied in noise-exposed situations, an
area where calculations and quantitative measures have dominated to date. In
the thesis work, I attempted to combine these perspectives.
To sum up, the thesis is about two of my major interests; sound and
landscape. It has been very interesting to work at the intersection between these
areas and, as it happens, this work has coincided with renewed interest in
sound within landscape architecture, in practice and in theory. I would like to
think that this is not a temporary trend, but rather a (re)discovery of a
fundamental design element within the discipline. With this thesis, I hope to
contribute to future explorations in sound.
Gunnar Cerwén
Alnarp, July 24, 2017
ah this silence / sinking into the rocks / voice of cicada
Matsuo Bashō, Yama-dera 1689
Contents
List of publications
11
Abbreviations and central concepts
13
1
1.1
Introduction
Sound in landscape architecture
1.1.1 Contemporary challenges in landscape architecture
Sonic experience
1.2.1 The nature of sonic experience
1.2.2 Environmental preference and noise
Health effects
1.3.1 Negative health effects
1.3.2 Positive health effects
Reflection: A relevant pursuit
17
18
20
21
21
23
25
25
25
26
Positioning of the thesis
Two sensory traditions
2.1.1 Environmental noise management
2.1.2 Sonic treatments in the design tradition: A review of seminal
publications in landscape architecture
Sonic research traditions
2.2.1 Sound studies
2.2.2 The soundscape movement and acoustic ecology
2.2.3 The soundscape approach to noise
2.2.4 Sound research in architectural disciplines
2.2.5 Reflection on sonic research traditions
Practice-orientated research pertaining to soundscape thinking and
design
2.3.1 The soundscape design process
2.3.2 Support tools
2.3.3 Evaluation of designed projects
Aim and Methods
2.4.1 Aim of the thesis
2.4.2 Specific aims of Papers I-IV
27
27
28
1.2
1.3
1.4
2
2.1
2.2
2.3
2.4
29
38
38
39
42
45
49
51
52
53
56
58
58
58
2.4.3 Two focus areas
3
3.1
3.2
3.3
3.4
4
4.1
4.2
59
Summary of Papers I-IV
63
Paper I: The role of soundscape in nature-based rehabilitation:
A patient perspective
63
3.1.1 Background and aim
63
3.1.2 Methods
64
3.1.3 Results
64
3.1.4 Discussion and outcomes
65
Paper II: Evaluating soundscape intentions in landscape architecture:
A study of competition entries for a new cemetery in Järva, Stockholm 66
3.2.1 Background and aim
66
3.2.2 Methods
66
3.2.3 Results
67
3.2.4 Discussion and outcomes
68
Paper III: Urban soundscapes: A quasi-experiment in landscape
architecture
69
3.3.1 Background and aim
69
3.3.2 Methods
70
3.3.3 Results
70
3.3.4 Discussion and outcomes
71
Paper IV: Soundscape actions: A tool for noise treatment based on
three workshops in landscape architecture
71
3.4.1 Background and aim
71
3.4.2 Methods
72
3.4.3 Results
72
3.4.4 Discussion and outcomes
73
Discussion of results
75
Understanding soundscape thinking in landscape architecture
practice
75
4.1.1 Increased interest in sound in landscape architecture: Influence
from the soundscape approach
75
4.1.2 A hegemony of vision in landscape architecture? A nuanced
critique and a reliance on environmental noise management
77
4.1.3 Shallow strategies: a call for a soundscape approach to noise 78
Soundscape thinking in landscape architecture : A relevant pursuit
79
4.2.1 Sonic experience
80
4.2.2 Sound and landscape architecture on a general level:
Activities, materiality and spatiality
81
4.3
4.4
4.5
4.6
5
Representation of soundscapes
Variation as an ideal soundscape
Facilitating soundscape thinking: A soundscape approach to noise
4.5.1 Defensive, offensive and creative strategies
4.5.2 Introducing a model for comprehensive action: Localisation,
reduction and introduction
4.5.3 Comparing two frameworks
Soundscape actions
4.6.1 Soundscape actions: Future developments and positioning
Concluding remarks and future prospects
84
86
89
89
90
91
92
99
101
Acknowledgements
104
References
107
List of publications
This thesis is based on the work contained in the following four research
papers, which are referred to by their respective Roman numeral in the text:
I
Cerwén, G., Pedersen, E. & Pálsdóttir, A-M. (2016). The role of
soundscape in nature-based rehabilitation: A patient perspective.
International Journal of Environmental Research and Public Health 13
(12), 1229.
II
Cerwén, G., Wingren, C. & Qviström, M. (2017). Evaluating soundscape
intentions in landscape architecture: A study of competition entries for a
new cemetery in Järva, Stockholm. Journal of Environmental Planning
and Management 60 (7), 1253-1275.
III Cerwén, G. (2016). Urban soundscapes: A quasi experiment in landscape
architecture. Landscape Research 41 (5), 481-494.
IV Cerwén, G., Kreutzfeldt, J. & Wingren, C. (2017). Soundscape actions: A
tool for noise treatment based on three workshops in landscape
architecture. Revised manuscript submitted on September 4th 2017 to
Frontiers of Architectural Research.
In the printed version of the thesis, Papers I-IV are reproduced with the
permission of the publishers.
11
My contribution to the papers included in this thesis was as follows:
I
All authors were involved in the writing process. As first and
corresponding author, I had general responsibility and performed the
majority of the writing for this paper. The study was based on interviews
that were originally carried out for a different purpose by the third author.
In Paper I, the transcript material was re-analysed with a focus on
soundscape. The new analysis and research design was carried out in a
joint collaboration in which all authors participated.
II
All listed authors participated in discussions concerning the research
design. I was responsible for the analysis and for writing the paper. Both
co-authors contributed to the writing process.
III As sole author, I was responsible for all parts of this study. The research
was based on a landscape design intervention, for which I had the main
responsibility for development. The design of the intervention was
discussed in an expert group, and the construction was carried out in
collaboration with Jitka Svensson, Martin Malmquist and Anders
Svensson. The research design was formulated together with Mats Lieberg.
I was responsible for data collection, aided on some occasions by Sigrid
Lönnerholm. In writing the paper, I received valuable comments from my
two supervisors, Carola Wingren and Mattias Qviström, and from
statistician Jan-Eric Englund.
IV All listed authors participated in the research design. I was responsible for
analysis of the material and for writing the paper. Both co-authors
contributed to the writing process. The study was based on three
workshops in different contexts, all of which I was responsible for
arranging. In two cases, the third author was involved as project leader.
12
Abbreviations and central concepts
COST
CRESSON
dBA
EEA
END
ENM
EU
HOSANNA
ISO
NBHBP
SPL
UN
WCED
WFAE
WHO
Auralisation
European COoperation in Science and Technology
Le Centre de Recherche sur l’ESpace SONore et
l’environnement urbain. An influential research
institute for sound and ambience research in
architecture, located at the architectural school in
Grenoble, France.
A-weighted decibel levels
European Environment Agency
Environmental Noise Directive
Environmental Noise Management
European Union
HOlistic and Sustainable Abatement of Noise by
optimised combinations of Natural and Artificial
means
International Organisation for Standardisation
National Board of Housing, Building and Planning
[Boverket]
Sound pressure levels
United Nations
World Commission on Environment and Development
World Forum for Acoustic Ecology
World Health Organisation
A technique that makes it possible to simulate what a
sound environment will sound like (cf. Vorländer,
2008). It can be compared to the corresponding term
for visual representation of landscapes, visualisation.
13
Environmental noise
directive (END)
Environmental noise
management (ENM)
Masking
Quiet areas
Soft fascination
Sonic experience
Sonotope
Sound pressure levels
(SPL)
14
An influential directive on noise implemented by the
European Union, 2002/49/EC.
Term used in this thesis to refer to a sound
management approach in which the focus is on
protection from noise and measurements of sound
pressure levels. This approach, which has also been
denoted defensive (Hellström, 2002; Amphoux,
1993), is the most established approach (Brown &
Muhar, 2004), although the soundscape approach to
noise has developed significantly in recent years (see
separate heading).
The introduction of a sound (masker) to reduce the
impact from another sound (target sound). There are
two different kinds of masking; energetic masking,
where the target sound becomes inaudible (or less
loud) when the masker is introduced, and
informational (or attentional) masking, where the
target sound is still audible, but the masker sound
shifts focus by drawing attention (Moore, 2012).
The END (EU, 2002) directive on noise stipulates that
member states should map and protect quiet areas.
Quiet areas have different definitions and applications
depending on context and member state and typically
vary between 25 and 55 dBA (cf. EEA, 2014).
A term coined and popularised by Kaplan & Kaplan
(1989) (cf. James, 1962) as part of their attention
restoration theory. It is described as an effortless state
of being that can facilitate recovery from fatigue.
A term used in this thesis to refer to the role sound
plays in the everyday experience. The term is broad
and includes, among other things, the connection
between sound and behaviour and preferences for
various environmental sounds.
Emphasises the connection between a certain type of
location and the sounds it is likely to produce
(Hedfors, 2003). A parallel can be drawn to the
concept biotope.
A critical parameter in discussions on sound and
particularly used in environmental noise management,
where it can be calculated or measured. SPL are
Soundscape
Soundscape action
Soundscape approach
to noise
Soundscape thinking
described on a logarithmic scale, decibels (dB),
usually A-weighted (dBA) to account for the relative
hearing sensitivity of the human ear in different
frequency bands. Moreover, SPL often refer to an
average (equivalent) value accumulated over a certain
period of time.
A broad concept that can have different meanings in
different contexts (Schafer, 1994 [1977]), e.g. to
describe musical compositions, field recordings and
art. In this thesis, the concept refers to the everyday
experience of the sonic environment. It is defined by
the International Organisation for Standardisation
(ISO) as the “acoustic environment as perceived or
experienced and/or understood by a person or people,
in context” (ISO, 2014).
A tool developed in this thesis for soundscape
consideration in landscape architecture and urban
design.
A term used in the thesis to refer to situations where
soundscape thinking is applied in noise exposed
situations. The soundscape approach to noise is
sometimes referred to as a comprehensive approach,
or a soundscape approach, but the longer form is used
in the thesis when there is a need to emphasise a
noise-exposed context.
A term used in the thesis to describe situations where
the experiential possibilities in the sound environment
are considered. Soundscape thinking can be used in
noise exposed situations, in which case it is akin to the
soundscape approach to noise.
15
16
1
Introduction
Landscape architecture is inherently related to sound. Whether the context is
urban or rural, the shaping of the land has far-reaching consequences for the
sonic environment. The sonic environment, in turn, influences people’s
experiences, health and wellbeing 1.
The relationship between sound and landscape architecture can be further
illustrated through appropriation of a metaphor proposed by the Canadian
composer R. Murray Schafer (1994 [1977]). Drawing on artistic work by John
Cage, Schafer suggests that the everyday sonic environment can be regarded as
a major continuously ongoing composition where everyone participates. All
sounds – whether they are created by footsteps on a gravel path, noise from a
car engine or conversations in a café – would be part of such a composition.
This metaphor is interesting, as it raises the enjoyment of everyday sound as
a topic to be discussed. In some contexts, discussions on environmental sounds
have been overshadowed by considerations about noise. Problems with noise,
while a significant issue, have tended to dominate discussions on sound and, it
could be argued, have given it a bad name.
The idea of a musical composition also implies that every environment can
be treated as a concert hall. Concert halls are generally given great attention in
terms of acoustic furnishings, but what about the everyday composition taking
place in ordinary streets, parks and squares? The passive acoustics of such
spaces are created, consciously or unconsciously, by the landscape architect.
The quality of materials used and spatial solutions determine how sound is
distributed in space. Shaping the land thus also involves shaping the passive
acoustics or, in other words, the prerequisites for the composition.
1
This introductory section summarises the background and starting points of the thesis. The
connection between sound, humans and the built environment is further elaborated and
substantiated throughout the thesis. The research situation is described in sections 1.2, 1.3 and 2.
17
Furthermore, because landscape architects are involved in decisions that
influence where and when different outdoor activities take place, one could
even go so far as to suggest that the landscape architect, in a similar manner to
a composer, arranges or directs the sonic environment.
Despite the possibilities in landscape architecture to influence the sonic
environment, there has been a perception that sound is mostly a concern for
trained specialists like acousticians and noise control engineers to deal with.
However, the past 15-20 years have seen increased awareness of the
possibilities in landscape architecture to consider sound. This development is
paralleled by a general interest in sound as a subject for research and design in
several disciplines in a wide variety of fields. However, as will be shown in
this thesis, there is still a tendency to neglect sound, or at least treat it in a
simplified manner in landscape architecture. This is problematic, considering
the documented effects that sound has on health and well-being.
Throughout the thesis, it is argued that sound could, and should, be better
integrated into landscape architecture and related practices, but that appropriate
tools, methods and strategies need to be formulated and made available. The
thesis sets out to achieve this through an investigation of the relationship
between soundscape thinking and landscape architecture practice.
The overall aim of the thesis was to facilitate soundscape thinking in
landscape architecture. Soundscape thinking is about allowing the experience
of sound to come forward when thinking about sound-space relationships. As
such, soundscape thinking entails problems as well as possibilities.
In the thesis, soundscape thinking has been applied in noise exposed
situations, as this was argued to be a good context to reach practitioners. This
application of soundscape thinking is denoted a soundscape approach to noise 2
in the thesis. Part of the challenge lies in combining two worlds: environmental
noise management on the one hand and design discourses and qualitative
considerations of sound on the other.
1.1 Sound in landscape architecture
Landscape architecture is a broad concept that includes the design and planning
of urban and rural areas. The scale on which the landscape architect works is
equally broad. It ranges from designing the individual planting bed in the
2
This approach has also been referred to as the soundscape approach (see e.g. De Coensel et
al., 2010), or a comprehensive approach (in the thesis). The longer form; a soundscape approach
to noise, is used in the thesis to emphasise noise-exposed contexts, and to avoid confusion with
soundscape thinking (which is not necessarily performed in noise exposed contexts).
18
private garden to laying out the structure of whole cities, or of roads through
regions.
The first use of landscape architecture as a professional term to refer to
design of outdoor environments can be traced to 1858, when Calvert Vaux and
Fredrick Law Olmsted described themselves as landscape architects in their
winning proposal for central park in New York (Turner, 1990). The profession
itself, although not specifically referred to as landscape architecture, is much
older than this, however. Geoffrey and Susan Jellicoe (1995) suggest, for
instance, that the first known examples of landscape design appear in cave
paintings in France and northern Spain, dating back to between 30,000 and
10,000 BC. Interestingly, it has been suggested elsewhere that these early
‘landscape architects’ also considered sound. For example, on performing
quantitative measures in Lascaux and other caves, Waller (1993) found that the
images depicting animals tended to be positioned where the acoustic qualities
of the caves would resonate sound, thus making it possible for animals to
“come alive”.
Similarly to other aspects in landscape architecture, awareness,
interpretation and application of sound-space relationships have undoubtedly
varied among practitioners, and in different cultures, contexts and eras. It is
beyond the scope of this thesis to investigate in detail how sound has been
treated in different contexts throughout history. Suffice it to say that there are
many interesting examples, ranging from the subtle sonic embellishments of
garden design features like suikinkutsu in edo-era Japan, through to the
mechanical singing birds found in oriental gardens and to the rich and clever
use of water features in Renaissance Italy.
It has been argued that, particularly during the modernistic era and onwards,
landscape architecture and related professions have failed to pay significant
attention to sound (Pallasmaa, 2012 [1996]; Jakobsson, 2009; Hedfors, 2003;
Lynch, 1976; Rasmussen, 1964 [1959]). This critique was first raised around
the mid-20th century and culminated around the turn of the 21st century. The
character and contexts of the publications concerned vary, but there is
generally a connection to a broader and more general reaction to modernistic
planning and architecture in the Western world, particularly concerning its
focus on visual expression in favour of other sensory experiences. This
reaction against what has also been referred to as “ocularcentrism” (Pallasmaa,
2012 [1996]) was fuelled in part by contemporary philosophical discourses on
modernity and its “hegemony of vision” (cf. Levin, 1993). It is argued
elsewhere in the thesis that there is scope for some of this critique, but it has
tended to be too categorical and has failed to articulate how consideration for
sound is lacking.
19
1.1.1 Contemporary challenges in landscape architecture
Contemporary landscape architecture discourses have been increasingly
concerned with sustainability and resilience. Questions like efficient land use
(densification), green and blue infrastructures, climate threats and the role of
natural processes are becoming increasingly important. Sustainability has
become established as a significant consideration within the field and there has
been renewed interest in the ecological approaches and ideas of the 1960s and
1970s, such as permaculture (Mollison & Holmgren, 1978), urban metabolism
(Wolman, 1965) and “design with nature” (McHarg, 1971 [1969]), as well as
newer contributions like cradle-to-cradle (McDonough & Braungart, 2002) and
landscape urbanism (Waldheim, 2006).
As a broad concept, sustainability includes aspects of social, economic and
environmental concerns (WCED, 1987), where it could be argued that sound
relates particularly to social sustainability (cf. Hedfors & Berg, 2003).
More than half the world’s population is now living in urban environments
(UN, 2014). While offering many qualities and much stimulation, the urban
environment may also be perceived as demanding and stressful, due to e.g.
attention-demanding stimuli and noise. Nature and nature-like environments
have been raised as important spaces for restoration by several researchers in
environmental psychology (Hartig et al., 2014; Stigsdotter et al., 2011; Kaplan
& Kaplan, 1989; Ulrich, 1984). The sound environment has been identified as
a key aspect to provide such tranquil qualities in urban areas, such as parks or
pocket parks (Pheasant et al., 2008; Nilsson & Berglund, 2006).
As densification proceeds and activities come closer, there is a challenge to
provide calmer areas required for recuperation. Consideration of soundscapes
is likely to become more important as space is used more efficiently.
Acoustically soft material, for instance, as found in vegetated soil (see e.g.
Nilsson et al., 2015), can be used to reduce unwanted sounds while at the same
time producing other ecosystem services. New physical structures of densified
urban spaces, if planned appropriately, can be used as screens that separate city
spaces acoustically (Hellström et al., 2013). The increased use of water in
retaining systems is also interesting from a soundscape perspective, as water
features can provide sound and offer masking capabilities (Brown &
Rutherford, 1994).
Technological developments also pose new challenges to soundscape
thinking. The increased use of vehicles driven by electricity rather than the
combustion engine can reduce the problem of noise. However, the new quiet
automobiles can be dangerous if they are not noticed, a fact that has led some
manufacturers to incorporate warning sounds as part of their machines.
Moreover, at speeds above approximately 30 km/h for light combustion
20
vehicles and 70 km/h for heavy combustion vehicles, problems with noise are
more likely to arise from the connection between tyres and road surface
(traction noise), rather than noise related to the engine and propulsion system
(Forssén et al., 2015). The problem with traction noise may in turn be reduced
by further development and application of quiet road surfaces and improved
tyre construction.
1.2 Sonic experience
The role of sound in environmental experiences is multifaceted. The following
section shows that sound is a factor to consider, not only in terms of problems
with noise, but also in terms of potential.
1.2.1 The nature of sonic experience
Physically, sound is a vibration caused by an activity. The vibrations cause
fluctuations in air pressure over time, resulting in sound waves that the human
ear can detect (Moore, 2012). One way of interpreting this relationship is that
activities speak to us through sound. Sounds are carriers of important
information about the environment. Whether they are induced by nature, man
or any other source, activities communicate through sound.
In comparison to human sight, which is limited to a field of vision of
around 180 degrees, human hearing can perceive sounds from any direction.
However, while the eyes have eyelids there is no corresponding mechanism for
the ears, which are continually immersed in sound.
To locate sounds spatially, humans rely on a number of perceptual cues and
mechanisms 3. Humans have a good ability to locate sound in the horizontal
plane (particularly left-right separation), but less so in the vertical plane (updown), and poor distance judgement (Moore, 2012). Overall, the ability to
locate sound is a useful factor to aid orientation in the environment (not least
owing to the ability to hear sounds from any direction). For instance, Schafer
(1994 [1977]) proposes the term “soundmark” to correspond with Lynch’s
(1960) more visually orientated term “landmark”.
3
There are several cues and mechanisms that humans use to locate sound sources in space. The
specific mechanism varies depending on where in the spatial plane the sound is coming from
(Moore, 2012). For instance, in order to distinguish between left and right, the brain makes a
calculation based on the difference between the signals that reach the ear on the respective side of
the head (interaural time difference and interaural level difference). On the other hand, to
distinguish between up/down and front/back, the shape of the pinnae is important (causing
frequency coloration that changes depending on the source’s direction).
21
A number of attempts have been made to explain how the sonic
environment can be listened to (Truax, 2001 [1984]; Gaver, 1993; Schaeffer,
1966). A recurring distinction is between active and focused ‘listening’ and
more passive ‘hearing’ that happens in the background. The attentive state, i.e.
listening, can be focused on different aspects, for instance physical qualities
inherent in the sounds or, as is most common among laypersons (Payne et al.,
2009), orientated towards sources. It is popularly argued that perception of
sound tends to be unconscious, as in hearing, making it prone to use in
subconscious “manipulation” (cf. Chion, 1994).
Sound has an ability to stir emotional responses, both positive and negative.
The auditory system is connected with the limbic (emotional) system of the
brain (Kraus & Canlon, 2012), a fact that can partly explain this. The
relationship between sound and emotion is well known and exploited in several
fields in society, including music, marketing and film sound.
Sound plays an important role in social communication, the most obvious
example perhaps being the sound of speech. In addition to speech, however,
there are several other social actions that are communicated through sound,
like the sound of movement, of working or of any other everyday activity. The
presence of other people can be effectively communicated through sound
(Gehl, 2006), an aspect that can be considered in city planning. The sounds
from a café or a market, for instance, offer potential qualities that can be
located strategically for atmospheric effects (cf. Alexander et al., 1977) or to
indicate territory (cf. Kreutzfeldt, 2009).
The interactive nature of sound should be emphasised, as human beings
have the possibility to create sound with their own bodies, as well as through
interaction with the surroundings (Thibaud, 1998). A walk on a gravel road in a
park, for instance, constitutes an activity that involves a continuous
contribution to the soundscape, as well as involving choices relating to how
and where to move. The sound of one’s own footsteps has been raised as a
potential quality that can be emphasised through material choices and other
aspects of landscape architecture (Cerwén, 2010a; Hedfors & Westerlund,
2004). The act of walking is interactive, and the sound reinforces and gives
feedback on the walker’s own movement (cf. Pallasmaa, 2006). Moreover,
people choose to attend to certain environments, while avoiding others (based
on sounds and many other aspects). In other words, perception of sound is not,
as is sometimes implied in acoustic disciplines orientated towards the natural
sciences, restricted to being a passive activity.
22
1.2.2 Environmental preference and noise
There have been a number of attempts to divide sounds into categories based
on the cause (source) of sound (Aiello et al., 2016; Krause, 2012; Matsinos et
al., 2008; Nilsson & Berglund, 2006; Schafer, 1994 [1977]). This thesis uses
an established division based on three categories: natural, technological and
human sounds (Nilsson & Berglund, 2006). Previous research has shown that,
generally speaking, sounds from natural sources are perceived as pleasant,
whereas sounds from technological sources are perceived as annoying
(Axelsson et al., 2010) and sounds from human beings are somewhere in
between. Such categorical preferences vary depending on other factors like
physical properties of sound, sound source, personal cues and context (Hong &
Jeon, 2015; Ratcliffe et al., 2013; Bjerke & Østdahl, 2004). Moreover, sounds
are seldom found in isolation, but in combination with other sounds.
Prominent sounds in the environment can mask the presence of other
sounds. For instance, some of the sounds produced by human beings are of a
relatively subtle character, which means that social communication can easily
be obstructed if the surrounding sound pressure levels are too high (Gehl,
2006). Similarly, other subtle sounds, like sounds from nature, can be masked
by noise. This, in addition to negative health effects (Basner et al., 2014),
indicates a need for a reduction in sound pressure levels in areas where such
issues are important.
The effect of traffic noise in masking out other sonic experiences can
perhaps best be understood in the limited numbers of cities, like Venice, where
automobiles are absent and the soundscape, as a result, becomes more
dynamic. The following description by American landscape architect Lawrence
Halprin, recounting his favourite urban experience, provides an example:
There was no sound - no automobile exhausts, no buses. Absolute quiet in the
very heart of a great city. In the distance you could hear faintly some young
people singing. All of a sudden the air became dark with birds, the square filled
with the beating of thousands of wings, the noise increased and increased until it
was deafening, and the deserted square became absolutely filled with pigeons.
The noise was incredible - even frightening. They had come to feed, and when
they had finished, they left just as quickly, and the great square was empty and
quiet again. (Halprin, 1973 [1963], 9)
The dynamic soundscape described by Halprin would be difficult to find in
many modern cities, where traffic and other white noise sources raise the
ambient noise level.
23
In addition to preference, noise can influence behaviour. It has been shown
that willingness to help other people with small tasks can be reduced if sound
pressure levels are high. In a review of such studies, Cohen and Spacapan
(1984) suggest that this behaviour change may be due to several probably
overlapping explanations, one of which concerns the masking effect of noise
on the social situation. Other suggested explanations include induction of a
negative state caused by noise, a changed focus of attention and a desire to get
away from the noise as quickly as possible.
To complicate matters, however, traffic sounds can be perceived as less
annoying in certain urban situations, where they may even be appreciated
(Anderson et al., 1983) and/or exciting (Whyte, 1980). It has been proposed
that such perceptual variations can be based on how well visual and auditory
cues correlate (relating to expectations on the environment). Using three
different methods Anderson et al. (1983) showed that expectation of the sound
environment had an influence on the rating of different audio-visual settings,
so that e.g. noise from road traffic was the most enhancing sound in an urban
setting. The congruence between auditory and visual stimuli was subsequently
confirmed in a laboratory setting by Carles et al. (1999), and to some extent by
Pheasant et al. (2010) and Viollon et al. (2002).
Viollon et al. (2002) argue that there is an additional mechanism that could
potentially override audio-visual congruence. Drawing on Björk (1995), they
suggest that some perceptual cues (like sounds from other humans) are more
attention-demanding, and thus less prone to be dependent on congruence
between different perceptual cues. There are also other related factors to take
into account, such as context and subjects’ expectations on the environment
(Hong & Jeon, 2015; Preis et al., 2015; Brambilla & Maffei, 2006). However,
it should be pointed out that, in the studies cited above, the purpose (e.g.
evaluation of tranquillity or aesthetics) and evaluation scale (e.g. degree of
pleasantness or enhancement) varied to some degree.
Noise has several definitions. In urban planning contexts and within
environmental noise management, noise has tended to be defined as unwanted
sounds (typically technological sounds), measured in sound pressure levels
(dBA). This would seem like a rather straightforward definition. However, as
Hellström (2003) argues convincingly, perception of noise can vary, and what
is noise for one person in one context may not necessarily be noise in another
context, or for another person. In addition, findings from studies like that
conducted by Anderson et al. (1983) and observations by Whyte (1980)
support the importance of contextualising and problematising noise treatment.
There is a need for better understanding of the perceptions of noise in planning
situations.
24
1.3 Health effects
1.3.1 Negative health effects
Much previous research concerning the effect of sound on human beings has
been concerned with understanding and mapping health effects related to noise
exposure. There is now a convincing body of available research that shows
correlations between noise exposure and negative health effects (Basner et al.,
2014; Stansfeld et al., 2000; WHO, 2000).
Exposure to noise can damage the auditory system and cause hearing loss
and tinnitus. Exposure to noise has also been shown to cause non-auditory
negative effects on health, like sleep disturbance, annoyance, cardiovascular
disease and hypertension. Furthermore, there is a connection between noise
exposure and problems with mental health (Beutel et al., 2016). The World
Health Organisation (WHO) has estimated that the combined burden from
noise pollution in the European Union amounts to somewhere between 1.0 and
1.6 million Disability Adjusted Life Years (DALYs) annually (WHO, 2011).
In addition to negative effects on health, exposure to noise reduces
environmental quality (Yang & Kang, 2005) and has been shown to reduce
subjects’ willingness to help other people (Cohen & Spacapan, 1984).
1.3.2 Positive health effects
The negative effects on health are well documented, while it is only quite
recently that research has started to investigate the potential for positive
effects. This strand of research has typically looked into the possibility that
sounds of nature, such as sounds from birds, vegetation or water, can reduce
stress levels (for a review, see Hägerhäll et al., 2017). Given the dominant
focus on natural sounds, this approach is also related to research in
environmental psychology that has identified links between experience of
nature and recovery from stress (Stigsdotter & Grahn, 2003; Kaplan & Kaplan,
1989; Ulrich, 1984).
Growing numbers of studies have found that sounds of nature can play a
part in recovery from stressful situations. In a laboratory study where subjects
were exposed to a psychological stressor (Alvarsson et al., 2010), it was found
that a nature sound played at 50 dBA increased recovery speed in comparison
with exposure to three different types of noises (varying between 40-80dBA).
Similarly, Annerstedt et al. (2013) found that subjects recovered faster after
stress when exposed to virtual reality nature with nature sounds, in comparison
with virtual reality nature without nature sounds. In a study investigating the
25
restorative potential of different soundscapes, Medvedev et al. (2015) found
that, in addition to recovery from stress, positive experience of sounds could
also reduce arousal in subjects at rest.
In healthcare, nature-based sound therapy is a method whereby sounds from
nature are played through speakers with the aim of reducing negative
experiences associated with treatments in difficult situations. Nature-based
sound therapy has been studied in practical situations and shows good effects
in reducing pain (Diette et al., 2003), as well as anxiety and stress (Saadatmand
et al., 2013).
To sum up, research thus far indicates that there is a relationship between
exposure to nature sounds and positive health effects relating to healing
processes in certain situations. However, a better understanding is needed of
this relationship in terms of contextual cues, types of sounds involved, physical
properties of sounds and interactions with other sensory inputs (cf. Hägerhäll et
al., 2017).
1.4 Reflection: A relevant pursuit
The above review illustrates how sound is a factor in environmental experience
and has a bearing on health. It also shows that sound can have positive or
negative effects in influencing environmental preference, wellbeing,
environmental interaction, social communication and health. Moreover, sonic
experience is complex and dependent on several different factors, including
sound sources, physical properties of sound, personal cues and contextual cues.
Noise exposure from technological sources can be associated with negative
health effects, as well as reduced environmental experience and infringement
on social interaction. Noise reduction would thus seem like a pertinent
undertaking in most cases, not least by allowing other, more subtle sounds to
emerge. In some cases, however, noise can be perceived as an urban quality,
underlining the importance of considering context.
In the remainder of this thesis, the sound-related outcomes described above,
and particularly problems with noise, constitute a basis to formulate strategies
for environmental design, where problems with noise can be addressed as part
of design solutions. Ultimately, the thesis presents a set of strategies and tools
by which landscape architects can consider sound in the design of outdoor
environments.
26
2
Positioning of the thesis
The following section outlines and describes prevailing traditions pertaining to
landscape architecture and sonic research. This is used as a foundation to
position the thesis and to formulate the aim and methods (see section 2.4).
The description of the field starts with a practice-orientated perspective and
outlines two traditions of sonic treatments in environmental design (section
2.1): environmental noise management and the design tradition.
The focus then shifts to a description and review of some of the sonically
orientated research traditions for addressing sound in and around architectural
disciplines (section 2.2). This review outlines four traditions; sound studies, the
soundscape movement/acoustic ecology, the soundscape approach to noise and
sound research in architectural disciplines. This is followed by a reflection
and positioning of the thesis in relation to these traditions (section 2.2.5).
A more detailed review of previous research, particularly focusing on
practice-orientated work, is provided in section 2.3.
2.1 Two sensory traditions
According to Lynch (1976), when it comes to treatment of sensory aspects in
urban planning, two general approaches or traditions can be discerned. On the
one hand, there is the environmental protection tradition, which for sound
corresponds to environmental noise management. This tradition is the newer of
the two, and for sound, it has been influential from around the 1970s in the
Western world (Goldsmith, 2012). On the other hand, there is the design
tradition which, according to Lynch (1976), is the older of the two and is
concerned with the qualitative and experiential aspects of sensory input. The
design tradition can be traced to classic architecture and landscape design.
Below, Lynch’s two traditions are used as a framework to outline how
sound is treated in and around landscape architecture. The environmental noise
27
management tradition is characterised by a quantitative approach to sound, and
its practice relies on trained professionals in acoustics (Bild et al., 2016a). Yet
landscape architects are likely to be involved in environmental noise
management to various extents, for instance in environmental impact
assessments for infrastructure developments.
The design tradition is more diverse and its development stretches over a
longer period. In order to outline the contemporary design tradition and
illustrate how the field has developed over time, a review of seminal
publications in the field between 1959 and 2012 was conducted.
2.1.1 Environmental noise management
It would be rather safe to suggest that noise, as in unwanted sound, has always
existed. The first known example of noise regulation, for instance, is said to be
from around 700 BC, when the province of Sybaris in Greece ordered that
tinsmiths, potters and other noise-generating tradesmen were to live outside the
city walls (Goldsmith, 2015).
Societies are continuously changing; old practices are abandoned, while
new are developed. People change their habits and make use of new technical
devices. This is also reflected in the soundscape. Much of what is considered
noise today can be traced to the industrial and electrical revolutions of the past
200-300 years, particularly white noise from infrastructure. While critical
voices were raised quite early against the new soundscape associated with
these rapid developments, it was not until the post-war era that environmental
noise policies to address the issue began to be developed in the Western world.
The first legislation to specify maximum sound pressure levels for traffic was
implemented in Chicago in 1957 (Goldsmith, 2012). In the 1970s, as part of
the influential environmental protection movement of the time, national
policies for environmental noise started to become established in the Western
world. From around that time, noise also began to be considered a major
problem that urban planners were obliged to deal with (Raimbault & Dubois,
2005).
Environmental noise management is today supported by well-documented
research on negative health effects (Basner et al., 2014) and is grounded in
large international organisations such as the WHO and the European Union
(EU). Noise from different sources, such as aeroplanes, trains, road traffic and
industry, is regulated in public policies on national and regional level. In
general, there are two stages that can be discerned in environmental noise
management: a diagnostic phase and a prescriptive phase (Bild et al., 2016a;
Gaver, 1988). The diagnostic phase involves measurements, calculations and
28
mapping of noise to gain an understanding of the prevailing situation. The
resulting diagnosis is then used as a starting point for the prescriptive phase, in
which counteractions, such as stricter regulations, noise screening or zoning,
are formulated.
In 2002, the EU implemented a new directive, commonly referred to as the
Environmental Noise Directive (END), which aims to define a common
approach for environmental noise management for member countries (EU,
2002). The directive has three objectives: determination of exposure through
noise mapping; information to the public; and adoption of action plans. The
directive is noteworthy as, in addition to focusing on noise, it also emphasises
the mapping and preservation of what are referred to as “quiet areas”, which
has opened the way for new applications relating to soundscape thinking (Bild
et al., 2016a; EEA, 2014; Brown, 2010b).
Environmental noise management has been criticised as being too focused
on sound pressure levels and failing to provide a nuanced understanding in
which the actual experience of sound is given due recognition (Hedfors, 2003;
Hellström, 2003). It has also been argued that environmental noise
management focuses mostly on residential areas and how sounds are perceived
from within dwellings, but fails to consider outdoor environments (Brown &
Muhar, 2004).
Sound pressure levels constitute the basis in environmental noise
management but, as the reviews in sections 1.2 and 1.3 illustrate, there are
many other factors to consider. Lynch (1976) argues for integration of the
environmental protection tradition and the design tradition. Such integration
has been initiated in recent years, as exemplified in the soundscape approach
to noise tradition (Section 2.2.3). Further development of the relationship could
aid the overall perspective and lead to technical solutions that are grounded in
design aesthetics.
2.1.2 Sonic treatments in the design tradition: A review of seminal
publications in landscape architecture
Tracing sound in design thinking requires a nuanced understanding in which
account is taken of different approaches and ways of thinking, as well as
changes over time. In order to provide such an understanding, a review of
seminal publications in landscape architecture and related design disciplines
was carried out and the results are summarised below. The review is based on
publications that are regarded as classics within Swedish landscape
29
architecture 4. The review focuses on how sound has been treated in the
different publications (rather than evaluating the extent of treatment). In
addition, the review pinpoints descriptions about how sound is treated within
the field, particularly focusing on a recurring critique of the discipline’s
presumed visual focus in different eras (see also section 1.1).
It should be noted that a review of this kind provides an academic
perspective that is not necessarily reflected in the practice of landscape
architecture and design. However, because several of the authors are involved
in practice, discuss practice and/or are orientated towards practice, the review
is also informative for the latter purpose.
The publications reviewed date from 1959 to 20012 and, in order to indicate
any changes over time, are reviewed here in chronological order.
Incidentally, the first publication to be reviewed is not from landscape
architecture, but it is included here as it has been influential in the field, not
least in terms of how sound is approached. Within housing architecture, one of
the first publications to raise sound in the Nordic context was “Experiencing
Architecture” by Danish architect Steen Eiler Rasmussen (1964 [1959]). It
criticises the modernistic movement through what could be described as a
celebration of architectural experience. In the final chapter, entitled “Hearing
architecture”, Rasmussen writes convincingly about the sound of architecture,
and how it is possible not only to see, but also to hear architecture:
Can architecture be heard? Most people would probably say that as architecture
does not produce sound, it cannot be heard. But neither does it radiate light and
yet it can be seen. We see the light it reflects and thereby gain an impression of
form and material. In the same way we hear the sounds it reflects and they, too,
give us an impression of form and material. (Rasmussen, 1964 [1959], 224)
That statement, and the chapter as a whole, suggest that sound was not a
normal consideration for architects at that time. While there was an existing
tradition to consider sound in special contexts, like concert halls, this was not a
concern in everyday architecture. Furthermore, treatment of sound in concert
halls was handled by acousticians rather than architects, but Rasmussen
describes how architects could also benefit from consideration of sound.
4
The selection is based on publications regarded as classics within the field at the author’s
Department. The publications were selected based on course reading lists, recommendations and
discussions with lecturers and researchers at the Department. They may not necessarily
correspond to perceived classics in other parts in the world, and influential works may have been
excluded.
30
Gordon Cullen’s treatment on city planning, “The Concise Townscape”
(Cullen, 1971 [1961]), is perhaps most famous for its sketches depicting the
progression of vistas as they develop while moving. In the presentation of his
three arguments, serial vision, relative positions and architectural fabric, Cullen
uses an approach akin to phenomenology, yet focuses on vision: “We turn to
the faculty of sight, for it is almost entirely through vision that the environment
is apprehended.” (Cullen, 1971 [1961], 8). Nevertheless, as also noted by
Hedfors (2003), Cullen makes reference to other sensory impressions,
including sound. However, these references tend to be used as descriptions that
reinforce the visual experience, rather than being reflections in their own right.
In terms of sound, Cullen mentions the contrast between noise and relative
silence, as well as echoing footsteps.
In “Cities” from 1963, American landscape architect Lawrence Halprin
(1973 [1963]) writes about some basic components of cityscapes, such as street
furniture, city floors and spatiality. The approach is clearly grounded in what
would now be called a phenomenological approach, and Halprin discusses, for
instance, the choreography of cities and the sensory experiences in urban
gardens as a contrast to the sometimes “overwhelming scale and density of
urban living” (Halprin, 1973 [1963], 37). Halprin makes great use of vivid
descriptions of sonic experiences, particularly in a section of the book that
describes water features: “Water has sounds as well. It gurgles, it splashes. It
goes plop, plop, plop. And fshzzzsh. And spaatzzz!” (Halprin, 1973 [1963],
143). In this way, Halprin connects to a long tradition of acknowledging
sensory qualities in water features. While he does not go into any detail about
how specific characters of sounds are to be created, his use of onomatopoetic
language suggests tacitly that such decisions could be made.
In 1969, Ian McHarg published “Design With Nature” (McHarg, 1971
[1969]), which would become an influential source in the field, not least for the
ecological movement that followed in the 1970s. The publication is well
known for its use of overlay maps as a way to understand and analyse
landscapes. McHarg shows, among other things, how sound pressure levels
could constitute one such map layer. A development of his method of
overlaying maps is potentially useful as a way for landscape architects to
understand and work with experiential qualities in sound, as illustrated by the
application of the method suggested by Hedfors (2003). The technique is now
established in various digital platforms, such as GIS. McHarg’s book would be
classified as landscape planning, yet it is interesting how he, in a similar way to
Halprin in “Cities”, makes use of rich descriptions of sonic experiences in the
introductory chapter, thus suggesting that his arguments are rooted in the
human scale.
31
In 1969, when reporting on a pioneering study on sounds in urban
environments (see section 2.2.4), Michael Southworth (1969) described a
profession relying on “the eye alone” to design urban environments, a situation
which he considered particularly problematic given the noisy technological
developments of the time: “it seems that even before attempting sonic design, it
will be necessary to confront the problem of existing city noise” (Southworth,
1969, 67). This statement implies that noise treatment and sound design are
two separate entities for Southworth, thus supporting Lynch’s (1976)
previously discussed observation of two distinct traditions.
Jan Gehl’s “Life Between Buildings”, which explores social life in cities,
was first published in Danish (Gehl, 1971). In a section devoted to “Seeing,
hearing and talking”, Gehl raises the sound environment as an important
prerequisite for social communication. He proposes that it is particularly
difficult to communicate verbally in environments which are exposed to
background noise of around 60dBA or more, but calls for significantly lower
levels, around 40-50 dBA (in subsequent publications adjusted to 45-50 dBA),
if subtle sounds like footsteps, soft voices or street musicians are to be heard.
Gehl goes on to raise a number of experiential benefits that come from
excluding traffic in urban areas, and mentions Venice and other quiet
cities/areas as examples.
Kevin Lynch is perhaps best known for his visually orientated analysis and
description of mental and conceptual images in “The Image of the City”
(Lynch, 1960). In “Managing the Sense of a Region” (Lynch, 1976), he
incorporates a different perspective when he discusses how the “sensuous”
qualities of regions can be managed, i.e. the phenomenological experience. The
approach is grounded in a critique of planning practice, which in Lynch’s view
has a tendency to forget about sensuous qualities. He suggests that the reason
could be that such aspects are considered “too obvious to dally over or, if not
obvious, then trivial – too unpredictable and too personal to be part of any
public discussion.” (Lynch, 1976, 3). Lynch goes on to argue the relevance
associated with consideration of the sensuous, proposes a number of norms for
implementation and discusses different aspects of the planning process in
relation to this.
In a broad publication on architecture and urban planning entitled “A
Pattern Language”, Alexander et al. (1977) present a comprehensive list of
253 “patterns” or solutions to design situations that they refer to as a new
language for designers. Sound is mentioned in several of the 253 patterns,
including the quality of sound in “quiet backs”, and the role of sound in
“entrance transitions”. The atmospheric presence of sound is a recurring theme,
32
and one which it is proposed can be designed through consideration of concrete
actions like the relative location of functions.
From 1970 onwards, William H. Whyte led a small research group that
conducted a number of social observations in New York, the results of which
are published in “The Social Life of Small Urban Spaces” (Whyte, 1980).
Based on the observations, and akin to Gehl’s (1971) “Life Between
Buildings”, Whyte describes a number of relationships between social
behaviour and the urban fabric. In terms of sound, and in contrast to Gehl’s
argumentation, Whyte’s report finds a positive correlation between urban noise
and social quality. Whyte argues that “where there is the most noise and
pollution”, there is also “the most action to look at” (Whyte, 1980, 72).
Another noteworthy example is Whyte’s description of the rather loud
waterfall in Paley Park in New York and the way this functions to mask out the
noise from the surrounding city. Whyte argues that the sound of the waterfall,
in addition to producing pleasant associations, offers a sense of privacy, as it is
difficult to hear other people in the vicinity. A similar observation has been
made in Japan, where the loud background sound in popular pachinko halls
excludes people from holding conversations (Ogawa & Cerwén, 2016), thus
producing a sense of privacy.
Written as a resource for new landscape architects, Norman Booth’s “Basic
Elements of Landscape Architectural Design” (Booth, 1983) describes some of
the central components in landscape architecture in an insightful manner. In a
section on water, Booth discusses the sound of water features and how changes
in movement and volume can be used to control the character of the sound,
thus supporting the desired “visual aspects of an outdoor space” (Booth, 1983,
256). Booth also discusses the relationship between human emotions and the
character of water sounds, and mentions how the “rhythmic motions of waves
against a shoreline may be quiet and peaceful, while the roar of a waterfall may
be motivating” (Booth, 1983, 256). Booth also illustrates how water sounds
can be used as a masking element in urban areas and raises a few examples,
including the above-mentioned Paley Park in New York and Freeway Park in
Seattle, Washington.
In a 1988 publication entitled “The Poetics of Gardens”, American
architects Charles Moore, William Mitchell and William Turnbull describe and
analyse historical gardens from a designer’s perspective. There are several
references to sound throughout the publication, and a short section entitled
“Filling with sound” in the first part is also devoted to the topic. In this section,
the authors acknowledge that, through garden design, sounds can be either
“attenuated or intensified” (Moore et al., 1988, 40), and mention biotopes for
birds as an example by which to intensify. They go on to describe how
33
associations can vary depending on the specific sonic character of different
water features, or the sound of wind in different trees.
In “The Language of Landscape” (Whiston Spirn, 1998), American
landscape architect Anne Whiston Spirn writes about the relationship between
humans and their habitat – the landscape. Spirn suggests that landscapes have a
language that it is possible to read and write, the skills of which are dependent
on the sensory apparatus. Spirn’s descriptions of landscapes are based on a
language which is rich with references to sound, and the subtle qualities that
can be related to it. The following passage is from a section dedicated to the
sensual and dynamic qualities of matter and illustrates how differences in sonic
qualities can contribute to define a space:
The courtyard of the hotel de Sully in Paris is a garden cloistered between the
raucous Rue de Saint Antoine and the stately Place des Vosges, quiet, protected
from street noise by massive stone buildings. Birds bring the space alive,
chirping from within ivy on the walls, hidden but for their sudden flitting and
the moving leaves. (Whiston Spirn, 1998, 97).
In another context in the same publication, Spirn (1998) describes how water
sounds can be used to mask traffic noise and mentions the waterfall in Paley
Park as an example. Spirn also describes a personal experience of how a
speaker installation in Parc de La Vilette influenced her in such a way that the
borders between music and environmental sounds became blurred.
In “The Eyes of the Skin: Architecture and the Senses” (Pallasmaa, 2012
[1996]), Finnish architect Juhani Pallasmaa applies a phenomenological
perspective to discuss architectural experience from a multisensory
perspective. He describes the contemporary practice as being visually focused
and draws on various sources from the arts, philosophy and phenomenology to
argue for what could be described as an aesthetics of the senses. In a section
devoted to sound, entitled “Acoustic intimacy”, Pallasmaa discusses the
atmospheric and enveloping character of sound. The role of sound in
architectural experience, he argues, constitutes an important, yet forgotten,
feature, as sound has the potential to communicate directly between space and
user in an interactive manner. Pallasmaa believes that “a space is understood
and appreciated through its echo as much as through its visual shape”, but that
“the acoustic percept usually remains as an unconscious background
experience.” (Pallasmaa, 2012 [1996], 50). Pallasmaa goes on to formulate a
short critique of the modern city and its inability to offer sonic experience:
“The wide, open spaces of contemporary streets do not return sound, and in the
interiors of today’s buildings echoes are absorbed and censored. The
34
programmed recorded music of shopping malls and public spaces eliminates
the possibility of grasping the acoustic volume of space. Our ears have been
blinded.” (Pallasmaa, 2012 [1996], 51).
Similar criticisms of the visual aesthetics have been made, in various
contexts, from the turn of the millennium onwards. In a discussion on the
aesthetics of atmospheres and acoustic ecology, German philosopher Gernot
Böhme argues that “city planning can no longer be content with noise control
and abatement, but must pay attention to the character of the acoustic
atmospheres of squares, pedestrian zones, of whole cities” (Böhme, 2000, 16).
Hedfors (2003) speaks of a visual (landscape architect) profession and
Hellström (2003) notes that architecture is commonly regarded as being about
static materials rather than “the immaterial”. Degen (2008) describes how
modern planning has a way of discouraging experience and sensual variation in
cities, while Botteldooren et al. (2008) describe a field that, up to that time, had
been visually focused. Furthermore, Botteldooren et al. (2008) argue that even
though environmental noise management is regarded as a “good” approach, it
has not been successful in all aspects and requires creative strategies as
complements.
In parallel to the growing criticism of the visual focus in the discipline,
which culminated around the turn of the century, it is possible to discern
increasing interest in what has been called “the immaterial” in landscape
architecture and related disciplines. At that time, architectural discourses
started to pay more attention to aspects such as phenomenology (Pallasmaa,
2012 [1996]; Pallasmaa, 2009; Holl et al., 2006; Seamon, 2000), atmospheres
(Thibaud, 2011; Böhme, 2010; Zumthor, 2006; Böhme, 2000) and sensory
impressions (Jakobsson, 2009; Degen, 2008; Barbara & Perliss, 2006; Ionides
& Howell, 2005; Zardini, 2005; Malnar & Vodvarka, 2004). Research
specifically dealing with sound in architectural disciplines was also conducted
at that time, the development of which is reviewed elsewhere in this thesis
(section 2.2.4).This development is to some extent reflected in more recent
literature in landscape architecture.
Landscape urbanism can be described as a discourse or collection of ideas
(Thompson, 2012), the formulation of which was initiated during the 1990s
and popularised in the influential publication “The Landscape Urbanism
Reader” (Waldheim, 2006). One of the main ideas in landscape urbanism is
that cities should be considered as processes, i.e. landscapes, rather than as
individual buildings, a view clearly related to ecological thinking. The
landscape architect’s working methods have been raised as another (and
closely related) issue in landscape urbanism. Sound does not emerge as a
significant concern in “The Landscape Urbanism Reader”, but it is mentioned
35
in relation to video representations of landscapes as discussed by Christophe
Girot:
It is important to reconsider the perceptual limitations that pertain to landscape
thinking in general. Why, for instance, has movement remained so marginal in
our visual and sensitive assessment of urban environments? Aren’t the fleeting
sounds of the city just as significant as the tweet of a bird [sic] in our
appreciation of a given place? (Girot, 2006, 96)
Catherine Dee’s “To Design Landscape” (2012) is a practically orientated
publication for landscape designers, including the formulation of design
principles and strategies, as well as a number of illustrated sample projects.
One of the design principles, denoted “Elemental register”, is concerned with
nature connectedness. Dee exemplifies how such connections can be enhanced
by “engaging multiple senses in addition to sight” to emphasise processes in
the landscape:
For example, a plant will be chosen because its leaves amplify the sound of rain.
A poplar might be selected for the way its canopy flutters in the slightest of
breezes. Orchestrating stones of differing shapes to manipulate flowing water
will heighten sounds and eddies. Conserving a tree that might otherwise have
been removed in construction leads to the continuance of birdsong. (Dee, 2012,
57)
Furthermore, several of the example projects chosen for the publication are
known for their soundscape thinking, such as “Paley Park”, “A sound garden”
and “Cylinder sonore”. Yet, surprisingly, the soundscapes of these gardens are
not discussed in the contexts where they are raised.
Reflections on the review
Having studied some of the most influential writings in landscape architecture
through a sonic perspective, a few general trends can be discerned.
First, sound is rarely the primary focus in any of the publications orientated
toward landscape architects. Few have dedicated more than a short section to
sound. Instead, when sound is mentioned, it tends to be in ad hoc situations,
and sometimes (particularly in the earlier publications) as part of a description
of visual experience. One way of interpreting this is that it could, to some
extent, be representational of the way in which the environment is perceived,
where sound constitutes one aspect of several interrelated stimuli experienced
simultaneously. Or, as the French composer Michel Chion describes the nature
36
of an everyday (multi-sensory) experience in “Audio-Vision – Sound on
Screen”:
It is morning; I open the shutters of my bedroom window. All at once I am hit
with images that stun me, a violent sensation of light on my corneas, the heat of
the sun if it’s a nice day out, and outdoor noises that get louder as the shutters
open. All this comes upon me as a whole, not dissociated into separate elements.
(Chion, 1994, 112)
A second point, which is closely related to the first, is the fact that few of the
early publications elaborate in a detailed manner on how sonic qualities can be
designed. While there are several examples of rich sonic descriptions
throughout the period, there are few detailed explanations that investigate the
relationship between concrete design actions and their potential effect on the
soundscape. It seems that several of the authors are intuitively aware of such
relationships, but they are not formulated until around the 1980s. This could
suggest that knowledge about sound was not sufficiently developed in order to
formulate design recommendations, or that it was not prioritised. Another
possible explanation is that sound is part of tacit knowledge among designers
and/or there are difficulties in representing soundscapes.
Third, noise is a recurring theme, predominantly raised as a problem.
Descriptions of how landscape architects could consider noise in their designs
are lacking, however. Problems with noise seem to be mostly perceived as a
problem for acousticians to deal with. Some of the more recent publications
raise the possibility of landscape architects working with acoustics. Masking is
a recurring theme, particularly from around the 1980s, and tends to be
described as a rather straightforward effect. Potential problems and limitations
with masking are not raised, however.
To sum up, the review of seminal publications in the field suggests that
sound started to become increasingly recognised as a significant issue during
the 1970s and 1980s, but that prior to this, it was mostly present as tacit
knowledge that was described ad hoc or as part of a “visual” experience. The
review confirmed, to some extent, the previously mentioned critique of the
field as being visually focused, but it also suggests that much of this critique
was unnuanced. There have been several interesting examples of sound
treatment in the field, yet there has been a lack of articulations of the role of
sound, at least until around the turn of the 21st century. In addition, the review
suggests that the connection between landscape architecture and environmental
noise management could be further developed.
37
2.2 Sonic research traditions
Studies on sound exist in all of the three major research cultures (natural
sciences, social sciences and humanities), yet the approaches and purposes
differ. For instance, sound is studied in all of the following, yet significantly
different, fields: psychoacoustics, acoustics, communication, music
psychology, art and film sound. These are also examples of fields that were
important in informing the present thesis work. In the review that follows,
however, the focus is on research traditions dealing directly with the
relationship between sound, humans and the built environment.
For the purposes of this thesis, a division was made into four traditions:
sound studies; the soundscape movement/acoustic ecology; the soundscape
approach to noise; and sound research in architectural disciplines. The review
is followed by a reflection and positioning of the thesis in section 2.2.5 and a
more detailed review related to this in section 2.3.
2.2.1 Sound studies
Sound studies constitutes a broad and interdisciplinary academic field, where
the common denominator is the understanding of sound and sonic practices in
society. Since its initial development in the late 1990s, sound studies has seen
different delimitations and definitions and has also been referred to as e.g.
auditory culture (Back & Bull, 2003) or hearing culture (Erlmann, 2004).
Pinch and Bijsterveld (2004, 636) describe sound studies as “an emerging
interdisciplinary area that studies the material production and consumption of
music, sound, noise and silence and how these have changed throughout
history and within different societies”. Sound studies could be regarded as a
subcategory of the even broader field of sensory studies from which it, at least
partly, evolved (Pinch & Bijsterveld, 2012a).
Sound studies focuses on sound and sonic practices in society and deals
with a wide variety of topics, including sound art, urban soundscapes, media,
musicology, listening cultures, historical soundscapes, the history of sonic
practices and politics (cf. Gandy & Nilsen, 2014; Sterne, 2012b; Back & Bull,
2003). Sound studies may, in this sense, be regarded as an umbrella term. The
field is also concerned with the interplay between topics, as in the mutual
relationship between music and soundscapes (Papenburg & Schulze, 2016).
Publications in the field include “Auditory Culture Reader” (Back & Bull,
2003), “The Oxford Handbook of Sound Studies” (Pinch & Bijsterveld, 2012b),
38
“The Sound Studies Reader” (Sterne, 2012b) and “The Acoustic City” (Gandy
& Nilsen, 2014).
Sound studies is interesting, not only through its contribution to an
increased understanding of sound in society, but also through its different
approach to understanding society (from a sonic perspective). In other words,
sound studies is interesting from an epistemological perspective, as it can
partly be understood as an ‘alternative’ analytical approach through which
society can be understood. Jonathan Sterne, for instance, speaks about sound
studies as an “interdisciplinary ferment in the human sciences that takes sound
as its analytical point of departure or arrival” (Sterne, 2012a, 2). Holger
Schulze (2016), similarly, argues for “sonic epistemologies” in science.
Sound studies may, in this sense, be regarded partly as an epistemological
counter-reaction to previous shortcomings in understanding society from a
sonic perspective in the human sciences (cf. Schulze, 2016; Pinch &
Bijsterveld, 2012a). Sound studies may also be regarded as “an intellectual
reaction to changes in culture and technology” (Sterne, 2012a, 3) or changes in
the way academia thinks about, and organises, disciplines (Sterne, 2012a).
Several of the topics that are dealt with in the present thesis relate to sound
studies, or are considered part of sound studies in some contexts. These topics
include urban soundscapes, acoustic ecology and soundscape design.
2.2.2 The soundscape movement and acoustic ecology
Research on soundscape was first initiated in the late 1960s (see e.g. Truax,
1974; Schafer, 1970; Schafer, 1969; Southworth, 1969; Schafer, 1967). Its
development is usually associated with Canadian composer Murray R. Schafer
and his colleagues in the World Soundscape Project, which he led from 1969
onwards. While previous attention to the sonic environment had tended to
focus on how to protect people from noise, this new branch of studies started
instead to explore the potential and qualities inherent in the sonic world.
One of the original intentions behind this undertaking was in fact to address
the same kind of problem as environmental noise management around the same
time, but from a different angle. Instead of considering sound as something
negative, the soundscape movement sought to present the sonic environment as
positive, and thus also worthy of protecting from noise. It was argued that this
path would stir a wider interest than environmental noise management had
done by that time. Schafer writes:
Noise pollution results when man does not listen carefully. Noises are the
sounds we have learned to ignore. Noise pollution today is being resisted by
39
noise abatement. This is a negative approach. We must seek a way to make
environmental acoustics a positive study program. Which sounds do we want to
preserve, encourage, multiply? When we know this, the boring or destructive
sounds will be conspicuous enough and we will know why we must eliminate
them. (Schafer, 1994 [1977], 4)
The origin of the concept ‘soundscape’ is somewhat unclear. The term is
commonly attributed to Schafer around the time of the World Soundscape
Project’s initiation in 1969. However, it was also used by Southworth in
connection with a contemporary project in Boston, the findings of which were
published in 1969 (Southworth, 1969). Schafer has since attributed the concept
to Southworth (Darò, 2013; Sterne, 2013). However, the term had been used
prior to this on an occasional basis in various publications, dating back to the
1930s, according to a search in Google Ngram.
The most influential source to date when it comes to soundscape research is
undoubtedly the 1977 publication by Schafer, “The Tuning of the World”
(Schafer, 1994 [1977]). It comprises a collection and organisation of Schafer’s
work, covering among other things the findings from the World Soundscape
Project. In “The Tuning of the World”, Schafer proposes how the soundscape
can be approached, understood and developed, and introduces a number of
methods and concepts to do so. Schafer’s standpoint in this undertaking can be
criticised as being conservative and normative, as he is clearly favouring rural,
natural and historical soundscapes over urban and modern correspondents (cf.
Hellström, 2003).
Other influential publications related to the World Soundscape Project
include the “Handbook for Acoustic Ecology” (Truax, 1978), which is
essentially a dictionary of acoustic terms and definitions. It was edited by
composer Barry Truax, who also authored “Acoustic Communication” (Truax,
2001 [1984]). It introduces what Truax calls “a communicational approach” to
understanding the sonic environment. This approach could be regarded as an
elaboration and adaption of the soundscape discipline into acoustic ecology
(Hedfors, 2003). Like ecology, the communicational approach emphasises the
interaction between the listener and the surrounding environment (through
sound). This interactive understanding of sound also acknowledges the active
part that the listener can take, for instance, in creating sound. Truax also
introduces a series of distinctions and conceptualisations.
A collection of international approaches on how to study soundscape,
“Soundscape Studies and Methods” (2002), edited by Helmi Järviluoma and
Gregg Wagstaff, was published in Finland in 2002. It covers a variety of
predominantly European approaches, as well as a contribution from Japan
40
describing some of Keiko Torigoe’s work in Tokyo and the Kanda soundscape
project (Torigoe, 2002). The soundscape tradition was established in Japan in
the 1980s and included early applications of soundscape design (Torigoe,
2007), as well as studies on the meaning of soundscapes (as in the Kanda
soundscape project) (Hiramatsu, 2006).
Soundscape is described in “The Tuning of the World” as a rather broad and
interdisciplinary term that may be employed in different contexts, varying from
musical compositions and radio programmes to the outdoor acoustic
environment (Schafer, 1994 [1977]). This broad way of defining soundscape
was intentional by Schafer, as he sought to stimulate the formulation of an
interdisciplinary field:
It devolves on us now to invent a subject which we might call acoustic design,
an interdiscipline in which musicians, acousticians, psychologists, sociologists
and others would study the world soundscape together in order to make
intelligent recommendations for its improvement. (Schafer, 1994 [1977], 4)
Today, soundscape is indeed studied, not in one but in several interconnected
fields of research. In 1993, an organisation to coordinate soundscape research
was formed, known as the World Forum for Acoustic Ecology (WFAE). It
followed in the same tradition as the World Soundscape Project, as members
from the original World Soundscape Project were also involved in forming the
WFAE. The latter describes itself as “an international association of affiliated
organizations and individuals in Europe, North America, Japan, and Australia
that share a common concern with the state of the world's soundscapes.”
(WFAE, 2017). Similar to the standpoints described by Schafer in “The Tuning
of the World”, WFAE takes a clear stand against noise from modern and urban
developments. Starting in 2000, WFAE publishes Soundscape: The Journal of
Acoustic Ecology.
The term soundscape is used in several other contexts besides the everyday
sound environment, including sound art, field recordings and music. In such
contexts, the term seems to be used particularly when there is a need to
emphasise a contextual experience of sound. The different meanings of
soundscape, while beneficial in some respects, can also cause confusion. For
instance, there seems to be an understanding among some professionals
working with environmental noise management that soundscape research is
concerned predominantly with positive aspects of the sonic environment (like
masking). This understanding might be related to the many parallel uses of the
term soundscape (many of which are found in the arts). In the present thesis,
soundscape is used to refer to the overall experience of the acoustic
41
environment or, as it is defined by the International Organisation for
Standardisation (ISO), an “acoustic environment as perceived or experienced
and/or understood by a person or people, in context” (ISO, 2014).
2.2.3 The soundscape approach to noise
For the soundscape movement, noise was a central concern already at the
beginning of the 1960s. Even though it was their focus on experience of sound
that received the most attention, noise was an important agenda too. For
Schafer (1994 [1977]), there was a dichotomy between noise, on the one hand,
and sound quality, on the other. These were considered to be opposite poles
that could not be combined and were referred to as lo-fi and hi-fi soundscapes
respectively. In “The Tuning of the World”, Schafer (1994 [1977]) argues
strongly against elevator music, muzak and similar strategies that try to mask
noise with “more sound”. Thus it is ironic that the soundscape concept is used
sometimes in environmental noise management as a way to refer to masking
strategies.
Somewhere around the 1990s, soundscape thinking started to become
increasingly incorporated into previously established areas focusing on
negative effects of noise 5 (cf. sections 1.3 and 2.1.1 of this thesis). While the
negative effects caused by noise were relatively well-documented at this time,
little research had problematised the field significantly and investigated to what
extent negative effects could be compensated for by other cues. As argued by
van Kamp et al. (2016) in a general discussion on human response to noise, the
negative health effects can be related to acoustic factors, like sound pressure
levels and frequency response but, can also depend on non-acoustic factors,
such as contexts, expectations and attitudes. Yet, the field had been mostly
focusing on the acoustic factors. Since the 1990s, there has been increasing
interest in the other mechanisms behind negative health effects, including
studies that further connect noise annoyance with the soundscape perspective,
thus merging the fields.
These initiatives have often focused on users’ experiences, in order to
understand how different factors influenced the perceived quality of the sound
environment, particularly in terms of possible reduction in noise disturbance.
One such factor that was investigated was how the quality associated with
‘positive’ sounds, like water sounds, could be used to mask noise (Rådsten
Ekman, 2015; Galbrun & Ali, 2013). Other central questions have included
5
This is commonly referred to as the soundscape approach (eg. De Coensel et al., 2010). In
the thesis, the longer form soundscape approach to noise is used to emphasise the noise-exposed
context and to suggest that soundscape thinking can be employed in other situations as well.
42
compensation strategies, like access to a quiet façade (de Kluizenaar et al.,
2011; Öhrström et al., 2006), access to nature (Pheasant et al., 2008; GidlöfGunnarsson & Öhrström, 2007) and visual connection (Botteldooren et al.,
2016; Pedersen & Larsman, 2008).
The Swedish research programme ‘Soundscape support to health’ (GidlöfGunnarsson et al., 2008), which was carried out between 1999 and 2007,
focused on sound environments for residential areas. Employing qualitative
methods, like soundscape walks, and quantitative surveys, the programme
problematised the relationship between noise annoyance and sound pressure
levels by showing that the perceived quality also depended on other factors,
like characteristic sound sources.
The programme introduced a methodology that would later be called “the
Swedish soundscape quality protocol” (cf. Axelsson et al., 2012; Axelsson et
al., 2010; Nilsson & Berglund, 2006), in which soundscapes are evaluated
based on their perceived pleasantness, perceived eventfulness and
characteristic sound sources (natural, technological and human sounds).
Another aspect investigated was the relationship between noise annoyance and
other aspects of environmental quality. It was shown, for instance, that access
to nearby green areas could have an effect in reducing long-term noise
annoyance, along with other positive health effects (Gidlöf-Gunnarsson &
Öhrström, 2007). The programme also found that it was possible, to some
extent, to compensate for noise annoyance through access to a quiet façade
(Öhrström et al., 2006), and this strategy was implemented as part of the 2002
directive (END) on noise in the European Union (EU, 2002). That directive has
played a part in integration of the soundscape tradition with environmental
noise management. In addition to the quiet façade, the notion of quiet areas
and mapping these are important (cf. Bild et al., 2016a; EEA, 2014; Brown,
2010b).
The relationship between soundscape thinking and noise has been further
studied by the research group led by Professor Jian Kang in Sheffield (Kang,
2010; Kang, 2007; Zhang & Kang, 2007; Yang & Kang, 2005). Among other
things, the group has been working with assessment of soundscape quality in
urban squares and thereby increased understanding of how characteristic sound
sources interact with sound pressure levels and other cues to influence
perceived sound quality. Yang and Kang (2005), for instance, found that
sounds that were perceived as positive could reduce annoyance “even when its
sound level is rather high” (Yang & Kang, 2005, 228), and suggested that this
finding supported the use of masking techniques to abate noise. Zhang and
Kang (2007) subsequently proposed a limit at 65-70 dBA, and argued that, if
43
the sound pressure level exceeds this limit, all sounds are disturbing and
masking techniques are not relevant.
As indicated in the review in section 2.1.2 masking has generally been
regarded as a fruitful and rather straightforward strategy in city planning.
However, besides Whyte’s (1980) explorative observations in Paley Park,
masking had not been studied in such contexts until rather recently. In her
thesis “Wanted Unwanted Sounds”, Maria Rådsten-Ekman (2015) investigated
the potential to use water features as a way to mask noise in urban settings. Her
work, which was based on three studies on users’ perception, showed that there
was potential for water sounds to mask noise, but that the masking doesn’t
necessarily improve the soundscape. It was found that water sounds with a low
loudness and of fluctuating character (as in rippling and purling water) were
preferred over sources with a high flow rate and akin to white noise. In other
words, in addition to sound pressure levels, successful masking is dependent on
other experiential characteristics of the inherent sounds as well.
The ‘Positive soundscape’ project was carried out as a collaboration
between five universities in the UK during 2006-2009, and the findings were
summarised in a scientific article (Davies et al., 2013). The project identified
three different areas to which descriptions of soundscapes could be ascribed;
sound sources, sound descriptors (descriptions of physical qualities of a sound)
and soundscape descriptors (descriptions concerning the combined effects of
several sounds, such as hubbub). The project also identified that the overall
character of soundscapes could be pinned down to two dimensions, or principal
components: calmness and vibrancy (Davies et al., 2013). This finding is akin
to the ‘Soundscape support to health’ project, and its use of pleasantness and
eventfulness to describe soundscapes (Axelsson et al., 2012; Axelsson et al.,
2010; Nilsson & Berglund, 2006).
More recently, there have been increasing efforts to collaborate on
soundscape research internationally, in order to reach common understandings
and guidelines. Much of this work can be related to the EU COST Action
collaboration ‘Soundscape of European Cities and Landscapes’, which
involved more than 30 countries within and outside the European Union
(Brown, 2012). The aim of the project, which was initiated in 2009 and ended
in 2013, was “to provide the underpinning science for soundscape research and
make the field go significantly beyond the current state-of-the-art” (COST,
2008, 2). A harmonisation of studies on soundscape was thus initiated in order
to simplify comparisons between studies on the topic, among other things. The
project also worked pragmatically with implementation of soundscape into
policies and legislation. The international collaboration in the project resulted
in e.g. the publication “Soundscape and the Built Environment” (Kang &
44
Schulte-Fortkamp, 2016), in which the project’s “consensus on the current
state of the art” is provided (Kang & Schulte-Fortkamp, 2016, back cover).
In parallel to the COST Action, another EU-funded project called
‘HOSANNA’ (HOlistic and Sustainable Abatement of Noise by optimized
combinations of Natural and Artificial means) was carried out. The
HOSANNA project investigated how alternative approaches, like the absorbing
characteristics of vegetated soil, could be used in city planning to reduce noise.
The project findings are reported in an illustrated brochure published online
(HOSANNA, 2013) and in “Environmental Methods for Transport Noise
Reduction” (Nilsson et al., 2015).
The international collaboration on soundscape is also reflected in the
previously mentioned ISO definition of soundscape (ISO, 2014) and the
SONORUS research programme for urban sound planning. The SONORUS
programme, which ran between 2012 and 2015, brought together young
researchers from around the world, all of whom were working on one or more
of the following six themes: planning skills, public outreach skills, prediction
methods, soundscaping, noise control engineering and a holistic approach. At
the end of the SONORUS programme, an illustrated booklet (Kropp et al.,
2016) summarising the situation in urban sound planning was published.
2.2.4 Sound research in architectural disciplines
The following section covers some of the research specifically relating to
architectural disciplines. Such research has been fuelled in recent years by the
establishment of sound studies, but the research tradition can be traced to the
1960s. As mentioned previously, some of the first experiments on city sound
experiences were carried out in the late 1960s, by the World Soundscape
Project (Truax, 1974) and by Michael Southworth (1969). Southworth’s work
differed from that of the World Soundscape Project because he came from a
city planning background (he was a student of Kevin Lynch, who in turn was a
student of Frank Lloyd Wright), rather than musicology or the arts.
Southworth’s (1969) work was explorative in character and investigated the
role of city sounds, particularly in relation to visual cues. In the article
reporting on the project, Southworth notes that the “visual experience of cities
is closely related to the sounds that accompany it” (Southworth, 1969, 65). He
goes on to discuss potential applications in city planning, including proposing
four strategies to deal with noise: “careful location of noisy activities, new
types of highway and street design, special vehicle design, and masking of
existing noise by added sound” (Southworth, 1969, 67). He also discusses the
relationship between architectural spaces and their acoustic characteristics.
45
Ten years later, in 1979, the research institute CRESSON was initiated.
Situated in the architectural school in Grenoble, the institute is well known for
its interdisciplinary research spanning architecture, ambiences and urban
sounds. The institute brings together researchers from different disciplines,
including sociology, philosophy, acoustics, architecture and music. Since most
of the research at CRESSON is published in French, its accessibility to the
wider research community was limited in the early years. Some of the
important publications are now available in English (see e.g. Augoyard &
Torgue, 2005). The work at CRESSON has also been summarised in English
by Augoyard (1998) and Hellström (2003; 2002).
Similarly to Schafer and the World Soundscape Project, CRESSON
approaches the sonic environment in a qualitative way. However, at
CRESSON the relationship between sound, subject and the architectural
environment is more emphasised. In one of the most influential publications
from CRESSON, “Sonic Experience – A Guide to Everyday Sounds”
(Augoyard & Torgue, 2005; Augoyard & Torgue, 1995), the conceptual tool
“sonic effect” is introduced as a way of handling or describing sound-subjectspace-relationships. Sonic effect consists of a list of 82 effects, which can be
categorised by means of three different and overlapping levels: 1) Major/minor
effects (16 major and 66 minor), 2) disciplinary context (six different contexts)
and 3) type of effect (five different themes) (Hellström, 2003). Augoyard &
Torgue (2005) refer to the sonic effect as “sonic grammar” and an
“instrumentarium” through which the sonic environment can be understood
and shaped.
Another major publication associated with the research environment in
CRESSON is “The Sonic Identity of European Cities” (Amphoux, 1993),
which has been made available in English through translations and essays by
Hellström (2003; 2002). It can be described as a methodological manual,
fuelled by concepts and terminology. In his work, Amphoux (1993) identifies
three possible approaches to urban sound environments. These have been
denoted in English by Hellström (2003; 2002) as: offensive, defensive and
creative approaches. A defensive approach is more or less equal to the
conventional established environmental noise management, where the focus is
on negative aspects of sound. In the offensive approach, on the other hand, the
focus shifts from noise to what people want to hear. The offensive approach, in
other words, is about diagnosing what is good, rather than what is bad
(Hellström, 2002). The creative approach focuses on how the acoustic
environment can be designed or composed, and how citizens can be made
aware of it.
46
Björn Hellström, a Swedish architect, conducted part of his thesis work
based on theories developed at CRESSON. His thesis, entitled “Noise Design”
(2003), could be described as an exploration of aesthetics in urban acoustic
space. The thesis particularly explores seemingly paradoxical situations, such
as situations in which noise becomes aesthetic or when unstable acoustic space
is perceived as stable, i.e. the metabolic effect (cf. Amphoux, 1993).
Hellström’s (2003) work is based on practical and artistic examples, combined
with theories and conceptual tools. This intersection between theory and
practice constitutes yet another paradoxical situation, which Hellström deals
with through descriptions and examples presented on a CD-ROM. Two
theories are central, both developed at the CRESSON institute in Grenoble;
“sonic effect” (Augoyard & Torgue, 2005; Augoyard & Torgue, 1995), and the
“The sonic identity of European cities” (Hellström, 2002; Amphoux, 1993).
Sonic effect, particularly the metabolic effect (in the 2005 translation by
Andrea McCartney and David Paquette, this effect is denoted
“metamorphosis”), is central throughout the thesis.
In more recent works from CRESSON, the focus has been less on sound as
an “isolated” perception and more on sound as part of a “holistic” sensory
fabric, as in the study of urban ambience (Chelkoff & Paris, 2016; Thibaud,
2011). ‘The Ambience Network’ – founded by CRESSON researcher JeanPaul Thibaud and based in France – concerns the relationship between
atmosphere and architecture where all senses (including sound) are considered.
Similarly, the ‘Sensory Cities Network’ is another international platform for
cross-disciplinary dialogue.
There is also an ambition within CRESSON to develop tools that are more
readily accessible to architects and urban planners; one such tool developed for
sound is called Esquis’sons! (Marchal et al., 2016; Rémy & Chelkoff, 2016).
Some of the work previously performed at CRESSON, while essential to
provide a thorough comprehension of sound, may seem too difficult to
implement for practitioners with no previous knowledge in the subject (cf.
Hällgren, 2012b). The Esquis’sons! tool, on the other hand, is developed to
allow the architect to sketch in real time and experience how different solutions
influence the sonic environment. Related tools for auralisation (cf.
visualisation) are being developed elsewhere (Kropp et al., 2016; Pelzer et al.,
2014; Hällgren, 2012a; Lundén et al., 2010).
In parallel with the research conducted at CRESSON and with the findings
from the World Soundscape Project popularised with the publication of “The
Tuning of the World” in 1977, application of soundscape thinking in
architectural disciplines was initiated.
47
One of the first attempts to incorporate soundscape thinking as developed in
the World Soundscape Project was by American landscape architect Kerry J.
Dawson in 1988. In an article entitled ‘Flight, fancy and the garden’s song’,
Dawson (1988) uses some of the nomenclature developed in the World
Soundscape Project to discuss the sonic character of natural biotopes as a
quality that can be considered in design of gardens. He describes his work as
being part of “a current shift in design away from an aesthetic based solely on
visual attributes, and toward qualities which offer variety in sensual
experience” (Dawson, 1988, 170).
In 1993, Keiko Torigoe designed a soniferous garden in Japan, based on the
concept of soundscape (Hiramatsu, 2006), for a memorial house for Rentaroh
Taki, a famous Japanese composer active around the turn of the 20th century.
The design was based on various considerations, including design for natural
biotopes and sounds of human activities (visitors to the site). In a description of
the design project, Torigoe (2007) proposes an expanded framework for design
based on four aspects: sounds of sound-producing devices and instruments,
sounds of human activities, sounds of nature and sounds in
memory/imagination.
The thesis “Site Soundscapes: Landscape Architecture in the Light of
Sound” by Per Hedfors (2003) describes another early attempt at applying
sonic thinking in landscape architecture. The thesis aimed to supply a field,
described as visually orientated, with techniques and methods through which
the potential in planning and designing for sound could be accommodated and
practically implemented. The approach was broad and qualitative; part of the
research methodology included “skilled listeners”, such as musicians, to
evaluate the sonic environment in relation to two landscape settings (one urban
and one rural) (cf. Hedfors & Berg, 2003). This resulted in an increased
understanding of how sounds can be discussed in landscape architecture, and a
model to aid such discussions was proposed (model of prominence). The thesis
also introduces a number of terms and concepts applicable to landscape
architecture practice, including sonotope and auditory refuge, and describes a
prototype for a CD-ROM-based tool aimed at aiding discussions on sound for
landscape architects. Some of the nomenclature originally developed in the
thesis has been further developed as an application available in iOS, the
soundscape characterisation tool (SCT) (cf. Cerwén et al., 2016; Berglund et
al., 2013; Hedfors & Howell, 2011).
A more recent contribution to the field of landscape architecture came with
the 2017 publication “Sound and Scent in the Garden” (Ruggles, 2017). It is a
broad collection of papers originally presented at a symposium in Dumbarton
Oaks in 2014. The publication, which is historically orientated, covers a broad
48
range of geographical, cultural and chronological contexts relating to landscape
architecture. It illustrates how sound has been used as a design element in
various contexts throughout history.
In “Spaces Speak, Are You Listening?”, digital acoustician Bary Blesser and
independent scholar Linda Ruth-Salter (2007) explore (passive) acoustic
qualities in architectural spaces through a broad and interdisciplinary approach.
In a similar manner as Rasmussen in “Experiencing Architecture” (1964
[1959]) and Pallasma in “The Eyes of the Skin” (2012 [1996]), Blesser and
Ruth-Salter (2007) point out the experiential potential inherent in passive
acoustics of everyday architecture, but in a more thorough way. Through
historical examples and the introduction of concepts such as “aural
architecture”, “acoustic arena”, and “acoustic horizon”, Blesser and RuthSalter (2007) increase understanding of the role and experience potential
inherent in architecture’s acoustics.
The Auditory Architecture Research Unit at Berlin University of the Arts
has developed a new and embodied approach for the study of auditory
activities in environments. The research, which is based on a case study on a
square in Berlin, has resulted in strategies and practices for implementation in
design of architecture, based on a phenomenological approach to sound as an
“aural surrounding world”. The case study and the group’s approaches are
described in the publication “Klangumwelt Ernst-Reuter-Platz: A project of the
Auditory Architecture Research Unit” (Arteaga et al., 2017).
Urban researcher and sound artist Jordan Lacey (2016; 2014) has combined
affect theory with his own artistic practice to formulate a tool for urban
soundscape design denoted as “sonic rupture”. Even though Lacey’s work is
based in artistic practice, the strategies seem to be applicable in other contexts,
including landscape architecture.
2.2.5 Reflection on sonic research traditions
In the above review, four sonic research traditions were outlined and described:
sound studies; the soundscape movement/acoustic ecology; the soundscape
approach to noise; and sound research in architectural disciplines. While
divided into four areas for the purposes of this thesis, these fields are closely
related and often overlapping.
Notes on interconnections between sonic research traditions
The soundscape movement was the earliest of the initiatives, and ultimately led
to the formation of a field denoted acoustic ecology. Acoustic ecology is
prescriptive, as it favours natural and traditional soundscapes over modern and
49
urban soundscapes. While this stance is supported by research on negative
effects on noise and preference studies on sound (see sections 1.2 and 1.3), it
fails to account for many of the qualities found in urban environments, such as
the excitement and eventfulness of a market.
The qualities of urban life, including social and cultural phenomena, are
better accounted for in sound studies, which could be described as a broader
and less prescriptive discipline than acoustic ecology. Sound studies is
sometimes considered an umbrella term, in which case it is inclusive of the
other fields.
The qualities of urban life are also accounted for in the tradition denoted
sound research in architectural disciplines, which is based on a deep
understanding of sound-space relationships. However, it seems that much of
the work carried out in that tradition has been too complex to be of direct
interest for the average practitioner, although it constitutes an important
resource to inform the other fields.
Acoustic ecology shares its aversion to noise with environmental noise
management (see section 2.1.1). It is surprising that it would take until the
1990s before these areas started to merge in what is denoted here the
soundscape approach to noise. Combining the qualitative thinking in acoustic
ecology with the quantitative thinking in environmental noise management
opens the way for optimal treatment of noise. The soundscape approach to
noise could be described as problem-driven in its focus on noise, yet this focus
does not exclude qualitative considerations of sound. On the contrary,
qualitative considerations constitute an important part (as in masking
strategies).
Positioning of the research areas in the thesis
All four research areas outlined were important in informing the thesis. A
problem-driven approach was considered a fruitful starting point to facilitate
soundscape thinking in practice. Problems with noise seem to make it possible
to introduce pragmatic applications of soundscape design in well-established
channels, as noise is already acknowledged as an important consideration in
society and in landscape architecture 6. By choosing to work in noise-exposed
6
Noise issues constitute an important factor for various stakeholders in society, not least in
relation to health problems. Such a focus therefore ensures relevance on a societal basis. In the
thesis, it was also a factor when study objects were chosen and finances secured. Noise is likely to
become increasingly important to consider as densification in urban environments proceeds. With
densification, the need for contrasting and restorative environments on limited space could be
expected to increase, a development which would call for increased knowledge in soundscapes to
deal with noise.
50
situations, it was argued that it would seem particularly relevant for
practitioners to consider sound.
However, it has previously been suggested that a problem-driven approach,
as found in environmental noise management, is not enough to stir the
imagination among designers (Brown, 2010b; Schafer, 1994 [1977]). The
soundscape approach to noise adds a qualitative perspective which seems
useful in this respect. The combination of the problem-driven approach with
qualitative considerations is not only more likely to stimulate interest, but
could also be considered a more optimal tool for working with noise, as it is
more comprehensive. Furthermore, if noise-exposed situations are approached
qualitatively and with a focus on design, they could be used as platforms to
potentially motivate further interest in soundscape and act as a bridge to
connect acousticians and architects.
All four studies in the thesis (Papers I-IV) focus on areas exposed to traffic
noise. In this respect, the general approach could be described as problemdriven. Yet, all studies were designed to focus on the experience of sound, and
the noise-exposed contexts of the studies did not exclude a deeper
consideration of sound-space relationships (as found in sound research in
architectural discipline).
To conclude, all four traditions outlined in the review above were important
in the thesis. The soundscape approach to noise was the most influential, but
the work was also informed by the other traditions, particularly sound research
in architectural disciplines.
2.3 Practice-orientated research pertaining to
soundscape thinking and design
Much of the early academic work pertaining to soundscape in planning and
design disciplines was concerned with raising awareness and formulating
theories and concepts for understanding sound and sonic experience, but the
past few years have seen an increased ambition to implement the soundscape
discourse in practice. This development has been fuelled in particular by the
soundscape approach to noise tradition described above.
This thesis aimed to contribute to this development through an approach
based in landscape architectural practice (for aim and methods, see section
2.4). For this reason, the following section presents a more detailed review of
previous practice-orientated research, based on a distinction between three
areas: the soundscape design process, support tools and evaluation of design
projects.
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2.3.1 The soundscape design process
Research on the soundscape design process can either be descriptive, as in
sharing experiences from projects that have been carried out, or prescriptive, as
in proposing strategies for soundscape design, or combinations of the two.
The Brown and Muhar (2004) “approach to the acoustic design of outdoor
space” (cf. Brown, 2012; Brown, 2010a; Brown, 2004) introduces a work
process by which the outdoor acoustic environment can be designed from a
sound quality perspective. The proposed work process is based on the
formulation of acoustic objectives, which can then be fulfilled by following a
number of steps that centre around identification of wanted and unwanted
sounds and their enhancement and reduction, respectively.
In another approach to soundscape design, Zhang and Kang (2007) propose
that considerations of sound can be divided into two general areas: sonic
activities and spatial aspects. Zhang and Kang also propose a decibel limit of
65-70 dBA, above which it is not appropriate to introduce new sounds to an
environment. If this level is exceeded, they argue, no sound should be added
unless a reduction is achieved beforehand. Based on this distinction and other
considerations, they propose a chart to illustrate a potential design process
(Zhang & Kang, 2007, 78). The chart is interesting, but it is surprising that it
only proposes a reduction of sound if the sound pressure level reaches 65-70
dBA (and not below this level).
Adams et al. (2009) introduced a process map to illustrate how soundscape
expertise could be incorporated in different phases of established urban
planning processes in UK. In addition to sketching out the potential roles of
various stakeholders, the map includes proposed activities such as sound walks
and soundscape simulations for different phases. The map has since been
incorporated into a soundscape design strategy proposed by De Coensel et al.
(2010).
As part of a case study on an urban redevelopment project, De Coensel et
al. (2010) describe the methodology used to transform a former urban
industrial site into dwellings and a park. Their approach, which emphasises the
importance of early-stage consideration for soundscape, is based on two
general steps. The first step constitutes positioning of building blocks in such a
way that sound pressure levels are optimised at facades and in the park. In the
second step, different sonic environments are created based on the varying use
of spaces and their existing sounds. The authors argue that “This will imply
creating different acoustic environments for different zones, from lively to
quiet, from natural to more urban” (De Coensel et al., 2010, 4).
Jennings and Cain (2013) formulated a framework based on three steps to
aid improvement of soundscapes. The steps are: 1) Describe soundscape
52
elements; 2) identify factors that could influence the soundscape; and 3) link
potential design interventions to perception effects. In the final step of the
framework, the Kano model is borrowed from product development to evaluate
soundscapes based on three factors: basics, performance and excitement.
It has been argued that soundscape design is not easily transcribed into general
guidelines, approaches or methodologies (Asdrubali et al., 2014), but that
soundscape design requires a participatory process. Participatory processes to
soundscape design that include sound walks and discussions on sonic
experience have also been suggested by Siebein (2010) and described and
applied in practice by Tixier (2002), Adams et al. (2006), Schulte-Fortkamp
(2010), Asdrubali et al. (2014) and Claus (2015).
The viewpoint described by Asdrubali et al. (2014) in the context of
soundscape design has also been raised in discussions on design processes in
other contexts. The idea that design processes can be described in a
prescriptive or rational manner has been the subject of some debate. For
instance, Cross (2001) argues that for architecture, rational models might be
problematic if they describe a process that is more akin to a scientific activity
than a design, and calls for design research based in practice.
In the present thesis, the intention was not to describe a process for
soundscape design, but rather to understand practice and formulate support
tools that could aid soundscape thinking. This was done through evaluations
and discussions on design projects (Papers I-IV) and development of tools to
support design processes (Papers II and IV).
2.3.2 Support tools
Today, growing numbers of support tools are being developed within
academia, some of which can be useful for architectural disciplines. For the
purposes of providing an overview, these are divided below into three types of
tools.
Conceptualisations of soundscapes
A number of attempts have been made to conceptualise soundscapes in models
and diagrams, to increase understanding of the role of soundscapes in
environmental experience. Such conceptual tools are typically used to illustrate
some of the factors that influence assessment of soundscapes, such as sound
source type, physical properties of sound, spatial composition of sounds,
contextual cues and personality cues.
53
One such model has been specifically developed in the context of landscape
architecture, i.e. the model of prominence (Hedfors, 2003, 36). It is based on a
distinction between the amount of prominent sounds and the amount of
background sounds in a given environment. Through an intersection between
these two dimensions, the model of prominence defines four types of
soundscape characteristics: mild, powerful, clear and crowded.
Based on a listening experiment involving one hundred listeners, Axelsson
et al. (2010) found that the dimensions “pleasantness” and “eventfulness”
could explain 50% and 18%, respectively, of the variation. A principal
component model was constructed based on the intersection between these
two dimensions, leading to four (additional) types of soundscape
characteristics: monotonous, exciting, calm and chaotic (Axelsson et al., 2010,
2844).
An illustrative framework to describe soundscape perception has been
proposed by Cain et al. (2008). The framework makes a distinction between
aspects that are easily measurable, like loudness (sound), and aspects that are
more dynamic and complex (scape). The framework stands out as it takes
account of spatial aspects like direction, proximity and foreground/background
in an illustration.
A system to describe soundscape evaluation in urban open spaces has been
proposed by Zhang & Kang (2007, 76). The system is based on the following
factors identified as influencing soundscape evaluation: source, space, people
and environment.
A comprehensive taxonomy to describe the acoustic environment is
proposed by Brown et al. (2011, 390). The taxonomy illustrates the
relationship between environments, expected sound source types and examples
of generated sounds.
Another comprehensive conceptual model introduced by Herranz-Pascual et
al. (2010, 6) centres on the interaction between person, activity and place in
the environmental experience and proposes several factors that influence this
interaction.
Tools to identify potential changes in soundscapes
In the above review of soundscape design processes, an approach proposed by
Brown and Muhar (2004) was described. In addition to suggesting a process
for acoustic design of outdoor space, their approach could also be considered a
tool for broadly identifying potential design options to improve soundscapes.
For instance, the approach is based on identification of wanted and unwanted
sounds, and possibilities to control wanted and unwanted sounds are discussed
briefly. However, few concrete examples are mentioned.
54
The findings from the HOSANNA project resulted in an illustrated
brochure entitled “Novel Solutions for Quieter and Greener Cities”
(HOSANNA, 2013). The brochure is interesting from an architectural point of
view, as it contains descriptions of a number of sustainable, yet
unconventional, approaches to noise treatments, many of which are related to
everyday solutions and decisions in landscape architecture and city planning.
The findings from the HOSANNA project were later adjusted and
formulated as a toolbox within the context of a collaboration project between
four major cities in Sweden, called ‘City sounds’. Development of the toolbox
was coordinated by Björn Hellström and it is based on illustrative icons, each
of which symbolises an approach to reduce noise impact, such as “low wall
with vegetation”. The icons are sorted in a way that is intended to reflect an
existing professional division, as it is argued that this is the best way to allow
collaborations over disciplines (NBHBP, 2016). Divisions are thus made
between the categories: building types; building solutions; screens; ground
surface; and traffic and sound quality, with buildings and screens containing
the majority of the icons. The tool has been published, in Swedish, in various
contexts (Hellström, 2016; NBHBP, 2016; City Sounds, 2013).
Based on his own artistic practice, urban researcher and sound artist Jordan
Lacey (2016; 2014) has introduced a tool for urban soundscape design. The
tool, called ‘Sonic rupture’, centres around five general approaches to
designing soundscapes: addition, subtraction, disclosure, passion and
transformation.
Techniques for representation of soundscapes
There are different techniques and approaches for representation of
soundscapes. Visualisation of soundscapes in qualitative maps is illustrated by
Vogiatzis & Remy (2014) and Aiello et al. (2016). Hedfors and colleagues
highlight the importance of language, including appropriate terminology, in
order to discuss soundscape issues (Hedfors & Howell, 2011; Hedfors, 2003;
Hedfors & Berg, 2003). That work has resulted in an application which can be
used to inspire conversations about sound through eight different dimensions,
one of which is onomatopoeics (Berglund et al., 2013; Hedfors & Howell,
2011). Hedfors compares his approach to wine tasting discussions, only for
soundscapes. There are also tools that can simulate soundscapes through
auralisation (Vorländer, 2008). This technique has been extended to allow
sketching with sound in 3-dimensional environments like Rhinoceros 3D and
Grasshopper (Marchal et al., 2016; Rémy & Chelkoff, 2016).
55
The above review of support tools illustrates that there are a number of
instruments available for urban design. However, there is scope for further
development and refinement. In a COST meeting discussing challenges in
soundscape research (Kang, 2010), one of the outcomes was that existing tools
need further development and that new tools for use by urban planners in
different contexts and stages of the process are needed. The present thesis
presents two tools (see Papers II and IV), both of which could be positioned as
tools to identify potential changes in soundscapes. Both tools stand out from
previous contributions as they have been developed in relation to landscape
architectural practice. One of the tools, a conceptual model for comprehensive
design, was introduced to evaluate entries submitted to a design competition
(Paper II). The other tool, the soundscape action (Paper IV), was developed
together with practising landscape architects, Master’s students, artists,
acousticians and other professionals. The collaboration with practice was
considered to be an asset, as it was argued that this would mirror a designer’s
way of thinking to increase validity (cf. Cross, 2001).
2.3.3 Evaluation of designed projects
Evaluation and assessment of soundscape is now an established field (see
sections 1.2 and 2.4.3). Much of the work conducted in this field has been
dealing with assessment of urban experiences, but relatively few have been
connected to design. There have been only a handful of projects to date in
which design projects are evaluated. These projects have typically involved
speaker sounds as part of the research methodology, thus bordering on art to
various extents.
In one such project, entitled ‘The interior sound design of high-speed
trains’, Billström and Atienza (2012) tested different additions of speakergenerated sounds as a means “to create a comfortable and appealing
environment” in high speed trains. The sound installations were developed
using a simulation of the in-train environment which made site-specific
experimentation possible. Using a listening test for evaluations, the authors
found that, while there were differences in results between the different
approaches applied, there was clear potential to use speaker sound if carefully
designed. Billström and Atienza (2012, 8) concluded that “added sounds can
improve/enhance environments previously experienced as noisy and
uncomfortable”.
In a case study of an urban square in Stockholm, Hellström et al. (2014)
explored methods and strategies to abate noise using a qualitative approach. A
sound art installation called ‘Sonic space’ was installed at three places in the
56
square. The installation consisted of a collage of sounds, including the sound of
wind in trees, birds at a distance, ocean sounds and sounds from barbecue coal.
The installation was designed so as to blend in with the pre-existing
soundscape in the square, yet at the same time mask noise through
informational masking (Moore, 2012). The psychoacoustic evaluation
indicated that there could be potential for adding sound as a way to abate noise,
but that methodological issues made it difficult to assess an installation that
was, in fact, intended to be experienced as a background element.
Another project incorporating speaker sounds, called ‘Musikiosk’, was
carried out in a pocket park in Montreal during two months in 2015 (Bild et al.,
2016b; Steele et al., 2016). In that project, visitors were given the possibility to
play their own music through a set of public speakers, thus appropriating the
space acoustically. Using a mixed-method approach, it was found that
Musikiosk offered a welcome addition to the park that had a positive influence
on the social dynamics (Bild et al., 2016b), and enhanced visitors’ mood
(Steele et al., 2016).
In addition to the projects mentioned here, which have been described
and/or assessed through research, there have also been a number of projects
(with and without speakers) that have not been followed up in this way.
Examples of such projects are given by Payne et al. (2009), Kang et al. (2016),
Cerwén (2010a; 2010b) and Axelsson (2010), and include ‘The sea organ’ in
Zadar, Croatia; the combined noise screen and water feature called ‘The
cutting edge sculpture’ along Sheaf Square in Sheffield, UK; the motorway
organ ‘Harmonic bridge’ in Massachusetts, US.; ‘Le cylindre sonore’ in Parc
de la Villette, Paris, and a ‘Sound garden’ in Seattle, USA.
As the above review indicates, only a limited number of projects have been
evaluated in terms of their soundscape design thus far. This is noteworthy, as
such example projects could be important in building arguments for integration
of soundscape thinking in practice. Moreover, design reflections from such
evaluations could be important in creating a knowledge base for future
initiatives. The present thesis contributes an evaluation of a design intervention
in an urban square (Paper III), as a quasi-experiment in landscape architecture.
57
2.4 Aim and Methods
2.4.1 Aim of the thesis
The overarching aim of the thesis was to facilitate soundscape thinking in
landscape architecture.
Landscape architecture is a multidisciplinary field, hovering in the borderland
between natural sciences, social sciences, art and humanities (Thompson,
2017). In the profession and in academia, landscape architecture draws on
methodologies found in a wide variety of fields. The present thesis follows in
this tradition and draws on methodological approaches from environmental
psychology and design studies.
Furthermore, the thesis work is characterised by a combination of
quantitative and qualitative methods. The intention with such a mixed-method
approach (Bryman, 2012) is to increase validity through triangulation of
results. The mixed-method approach is also considered beneficial as it provides
the opportunity to understand general trends while at the same time permitting
nuanced and richer understandings of the research material.
The thesis is practice-orientated. It sets out to understand how landscape
architects work with sound today in order to understand how they could work
with sound in the future. Soundscape thinking is used to emphasise the overall
experience of sound, where problems and possibilities are accounted for.
Soundscape thinking is also used as a means by which to discuss and
understand the role of sound in planning and design situations.
The thesis consists of four studies (Papers I-IV), each of which was
individually designed based on a specific aim and context. The studies are all
part of the general aim of the thesis, but they also differ in that they are based
on different empirical material, focus on different areas and apply different
methodologies.
2.4.2 Specific aims of Papers I-IV
This section introduces each of the four studies briefly, focusing on their
specific aims. For an extended summary of the studies, including their
respective methodological approaches and findings, see section 3.
Paper I examined the role of soundscape in nature-based rehabilitation
through a study of interviews conducted with 59 caretakers in a
rehabilitation garden in Sweden. The aim was to examine the role that
58
soundscapes can play in nature-based rehabilitation for patients
suffering from stress-related mental disorders, and to identify essential
aspects to consider in future design of restorative spaces for mental
recovery.
Paper II centred on a design competition for a new cemetery outside
Stockholm; 109 competition entries were studied in the paper. The aim
was to increase understanding of how soundscapes are addressed in
the landscape architecture profession, and to develop a model for use
in evaluation of soundscape intentions in landscape planning and
design situations.
Paper III describes a design intervention built in an urban square. The
aim was to increase understanding of how the urban soundscape can
be altered through the design and construction of outdoor space.
Paper IV was based on three soundscape design workshops in
landscape architecture conducted on different occasions. The aim of
the paper was to collect and describe experiences from these
workshops, and analyse and structure the workshop proposals in a way
that made the outcomes accessible to practitioners. Paper IV
introduces a tool denoted ‘soundscape actions’.
2.4.3 Two focus areas
The thesis work was divided in two general methodological areas or
approaches; understanding sonic experience and understanding design practice.
Studies on sonic experience could be positioned within environmental
psychology, whereas studies on design practice could be described as design
studies. From a design perspective, the two areas are closely related, as an
understanding of sonic experience is a prerequisite to designing soundscapes.
Furthermore, sonic experience can be used as a method to evaluate design (cf.
Paper III). Both areas were used in different phases of the thesis work, and
were considered to be of equal importance in achieving the thesis aim of
facilitating soundscape thinking in the discipline.
In the following, the two research areas are discussed in relation to Papers
I-IV.
59
Understanding sonic experience
Sonic experience is a broad term used here to describe the phenomenological
influence that everyday sounds have on human beings. Sonic experience can be
about preferences for various sounds in the environment, or the relationship
between sound and human behaviour. It can also be about disturbance of
sound 7.
Assessment of sonic experience can be used to inform and/or evaluate
design projects. In this thesis work, both Paper I and Paper III incorporated a
methodological approach that focused on sonic experience.
On a general level, the study of human preference is difficult, as it entails the
translation of something as intangible and ephemeral as an experience into
words, explanations and concepts. This is a challenge for all preference studies.
However, in relation to studies on the visual, the vocabulary to describe sonic
events seems to be less well developed. Although inspiration can be found in
other fields, like music or cinema (Hedfors & Howell, 2011), communication
difficulties have been raised as an obstacle to understanding and clearly
articulating the role of sound (Raimbault & Dubois, 2005; Hedfors, 2003). In a
parallel way to images for visual representations, field recordings have been
suggested as a potential complement to other forms of sonic representations
(Prior, 2017).
Another challenge associated with studies on sonic preference is that human
beings tend to listen to everyday sounds in an unconscious manner. This
presents a potentially problematic situation, particularly when working with
self-reporting (as in Papers I and III). Once participants agree to answer
questions about their perception, they start to listen in a different way than they
normally would (cf. Schaeffer, 1966). This is an issue that should be given
more attention in the field, although it has already been identified as a
challenge (Rådsten Ekman, 2015; Hellström et al., 2014; Cerwén, 2009). One
way to approach it is to work with additional methods, such as evaluation of
behaviour and movement patterns (Aletta et al., 2016b; Bild et al., 2016b;
Lavia et al., 2016). It would be fruitful to conduct more studies that triangulate
self-reporting with other methods, as this could be used to evaluate the
credibility of self-reporting in various contexts.
Sonic experience has mostly been studied in terms of preference for various
sounds in the environment, as in the study of acoustic comfort (Yang & Kang,
2005), soundscape quality (Nilsson & Berglund, 2006) or pleasantness
7
Noise disturbance constitutes an important part of sonic experience, yet health effects related
to long-term exposure to noise are not covered in the concept or in this thesis. The significance of
such studies should nevertheless be acknowledged here.
60
(Viollon et al., 2002; Carles et al., 1999) or as part of visual aesthetics
(Anderson et al., 1983). Studies on behaviour are fewer, but have been
increasing rapidly in recent years (Aletta et al., 2016b; Bild et al., 2016b; Lavia
et al., 2016; Cohen & Spacapan, 1984).
For the purposes of assessing soundscapes in the present thesis, the Swedish
soundscape quality protocol (cf. Axelsson et al., 2012; Axelsson et al., 2010;
Nilsson & Berglund, 2006) was used as a general starting point to formulate
research approaches. However, the specific approaches varied depending on
context. In Papers I and III, the evaluation was carried out in situ. Studies in
situ can be problematic, as there are confounding factors to consider. Yet such
factors can also be beneficial, as contextual information can be important in
understanding how soundscapes interact with other cues in the environment. In
this thesis, studies in situ are thus considered equally important and
complementary to studies in controlled laboratory environments.
In Papers I and III, interviews constituted an important part of the research
to understand preferences in soundscapes. In Paper I, the interviewees were not
asked specifically for sound, yet mentioned it spontaneously. In Paper III,
interviewees were aware of the purpose of the study and, once they had
participated, talked about the study in a reflective manner. In both cases, the
interviewees were not experts in sound, and it was clear that several
descriptions were rather shallow (even though there were many rich examples
too). Moreover, a few interviewees struggled with their descriptions of sonic
experiences, which was a limiting factor in some cases.
The outcomes of the interviews were considered to be valuable in the
contexts in which they were studied, yet it was also clear that interviews with
laypersons had limitations. When the intention is to gain a deeper
understanding of the sound environment, it is probably more fruitful to involve
‘skilled listeners’ such as musicians and acousticians, as part of the
methodology (cf. Hedfors, 2003). Professionals with experiences from working
with sound are more likely to be able to reflect and discuss sonic issues on a
deeper level.
It should be mentioned here that, from a designer’s perspective, assessment
of soundscape is a limited method, in the sense that it generally requires
projects to be built or simulated. Design proposals cannot be easily assessed in
this manner (yet), but require simulations based on auralisation techniques.
61
Understanding design practice
The other focus area, design practice, was directed towards landscape
architecture as a cultural and professional practice. Here, the focus was to
understand how landscape architects work/do not work with sound and how
they could work. In other words, the study of design practice attempted to
understand how contemporary practice works (as in Paper II and to some
extent Paper I), but also to come up with fruitful strategies and approaches for
future work (Papers III and IV). Both perspectives were considered to be
essential for achieving the thesis aim of facilitating soundscape thinking in the
field.
Design practice was studied in a number of different contexts, including
design workshops, design projects and an architectural competition. The
methodological approaches varied depending on context, but much of the work
related to design evaluation, i.e. the application of a set of “measurable criteria
or standards [to generate] new knowledge about a situation or phenomenon”
(Deming & Swaffield, 2011, 180). In addition to the studies presented in
Papers I-IV, the review of seminal publications in section 2.1.2 was used to
form an understanding of design practice.
In the studies pertaining to design practice, the research design entailed
organisation of workshops (Paper II) and a design intervention (Paper III). This
required additional efforts, but resulted in valuable insights. The approach in
Paper III proved to be a useful way to study soundscape design, as the actual
construction could be evaluated in situ. The construction of a design
intervention in a public square also stimulated interest, from the media and the
general public. In this sense, the intervention not only functioned as a scientific
quasi-experiment, but also as a kind of forum through which the contemporary
soundscape could be discussed, thus bordering on an artistic statement. The
intervention also stimulated increased awareness and heightened listening, as
the following quote from one respondent illustrates: “It is even more disturbing
now than usual, as [the] questions make you focus on all the negative. Ugh”.
There is also a relationship here to the sound walk and other listening exercises
(cf. Schafer, 1992).
In Papers II and IV, the research did not follow an established methodology
and it was unclear from the onset exactly how the method could best be
designed. A suitable research design required an initial understanding of the
material. This approach could be described as explorative and was partly a
result of methodological insufficiencies within the field. Papers II and IV make
a methodological contribution that can be used as a starting point in future
work.
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3
Summary of Papers I-IV
This section provides an overview and summary of Papers I-IV. The summary
includes background, aim, method, results, discussion and outcomes for each
of the four papers. The papers are available in full as appendices in the printed
version of the thesis and online as indicated in the list of publications.
3.1 Paper I: The role of soundscape in nature-based
rehabilitation: A patient perspective
Figure 1. Image depicting the Alnarp rehabilitation garden (Paper I).
3.1.1 Background and aim
Paper I investigated the role of soundscape in a nature-based rehabilitation
(NBR) garden in Alnarp, Sweden (Figure 1). The study was based on
transcribed interviews with 59 patients suffering from mental fatigue, who had
participated in a 12-week long rehabilitation programme in the garden. The
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interviews were conducted over a five-year period (2007-2012) by the third
author, Anna María Pálsdóttir, with the original intention of investigating the
general role of nature in nature-based rehabilitation (cf. Pálsdóttir et al., 2014).
Sound was thus not an aspect that had been specifically addressed in the
interviews, but had materialised as an important aspect in the analysis.
3.1.2 Methods
In Paper I, the transcribed interviews were re-analysed, this time with the focus
on soundscapes. Relevant sections in the material were identified through the
use of keyword searches, in which 27 of the 59 patients were found to have
mentioned sound. All authors analysed the resulting material individually,
using interpretative phenomenological analysis (IPA) (Smith & Osborn, 2003).
All mentions of sounds were categorised as one of three sonic themes: natural,
technological or human-induced sounds (Axelsson et al., 2010; Nilsson &
Berglund, 2006). Following individual analysis, the authors discussed and
agreed on general findings.
3.1.3 Results
The findings indicated that sound could play a significant role in patients’
recovery processes. Sounds perceived as pleasing could aid the process,
whereas sounds perceived as intrusive could hinder it. For patients who
suffered from an increased susceptibility to sound, spending time in the garden
seemed to be able to mitigate recovery.
Natural sounds were generally perceived as positive and were referred to as
being part of an ideal and, somewhat paradoxically, “quiet” environment.
Furthermore, descriptions of nature sounds seemed to include references to
other (simultaneous) sensory inputs in a manner that was reminiscent of the
notion of “soft fascination” proposed by Kaplan & Kaplan (1989), and prone to
evoke memories.
Technological sounds were consistently referred to as problematic, but the
level of disturbance was set in relation to other environments to which the
patients were accustomed. Noise from a nearby motorway made some patients
move to areas in the garden that were less exposed to the noise.
Human-induced sounds were the most complex of the sonic themes and the
perception varied depending on social context and loudness. For instance, the
soft, gentle voice of a therapist could be referred to as a supporting feature,
while sounds from loud and/or unwanted participants were problematic. The
64
sound of gravel could be taken as a warning signal to inform patients about
other participants approaching.
The findings suggested that the interconnectedness between sound and
other sensory inputs could be of value for the recovery process and possibly an
important aspect to induce soft fascination. For instance, sonic feedback from
the patients’ own movement in the garden, particularly the sound of a wooden
deck, was mentioned as soothing.
3.1.4 Discussion and outcomes
Paper I presents a discussion on the role of sound in nature-based rehabilitation
and in relation to this, investigates potential design considerations. It proposes
that, in order to optimise nature-based rehabilitation, the design of future
gardens should include consideration, not only for reduction of noise, but also
for measures to enhance appreciated sounds. This could be described as a
comprehensive approach (cf. section 4.5). Furthermore, a varied soundscape is
proposed in Paper I as a means through which each patient would have the
possibility to seek out their favourite environment, based on aspects such as
personal preference, mood and phase of treatment.
Natural sounds emerged as the sonic theme that was most supportive of
rehabilitation, and the discussion included a review of relevant literature
through which supporting biotopes could be created. This covered, for
instance, sounds from vegetation, water and birds.
Paper I proposes that sound requires further attention in nature-based
rehabilitation. In addition to understanding sound (in isolation), it would seem
to be important to study the interaction between sonic themes, as well as the
relationship between sound and other senses, as the significance of such
interactions were indicated in the study. Finally, Paper I proposes that sound
could be a useful means to inform general theories dealing with nature-based
rehabilitation.
65
3.2 Paper II: Evaluating soundscape intentions in
landscape architecture: A study of competition
entries for a new cemetery in Järva, Stockholm
Figure 2. Aerial photo of the Järva cemetery competition site (Paper II).
Photo: Lennart Johansson.
3.2.1 Background and aim
Paper II aimed to increase understanding of how soundscapes are addressed in
landscape architectural practice. The study concerned a major architectural
competition for a new cemetery in Järva, Stockholm. The competition area
(Figure 2) was problematic in terms of noise, making it particularly interesting
from a soundscape perspective. A total of 109 competition entries were
analysed, using a model developed in Paper II. In addition to increasing
understanding of landscape architecture practice, the paper also aimed to
evaluate the model.
3.2.2 Methods
A model for evaluation was introduced based on three main categories: I)
Localisation of functions, II) reduction of unwanted sounds and III)
66
introduction of wanted sounds (see also section 4.5). Each of the 109
competition entries was evaluated based on how it addressed these three
categories. This approach made it possible to evaluate the rather large number
of competition entries quantitatively, while at the same time allowing for a
more nuanced understanding through cross-category comparison. In addition to
the quantitative evaluation of the competition entries, one of the competition
entries that covered all three categories was described in more detail.
3.2.3 Results
The results showed that, given the problematic situation with noise at the
competition site, sound was given relatively little attention in the competition
entries. One-quarter of the competition entries did not address sound at all.
When sound was considered, this was generally done in a simplified manner
that typically involved noise screens (category II). It was relatively unusual for
competition entries to consider more than one of the three categories and only
five proposals considered all three categories (Figure 3). This can be related to
the fact that categories I and III were found to be underrepresented in the study.
Figure 3. Overview of how the three categories (I: localisation of functions, II: reduction of
unwanted sounds, III: introduction of wanted sounds) were combined in the 109 competition
entries studied in Paper II. Entries in Group A addressed zero categories, entries in Group B
addressed one category, entries in Group C addressed two categories and entries in Group D
addressed all three categories. The diagram also indicates the combinations of categories
addressed.
67
One of the competition entries that considered all three categories (entry no.
9, ‘Alice’) was examined more closely and is described in Paper II, as it was
considered a good, illustrative example of how the three categories could be
combined and how sonic issues could be dealt with.
3.2.4 Discussion and outcomes
Some general trends found in the competition are raised and discussed
in Paper II:
Extensive use of buzz phrases: It was common among competition
entries to refer to their proposed cemeteries in terms of being “quiet”
and “tranquil” places. However, these visions were seldom followed
up in terms of adequate soundscape actions.
A defensive approach: The main focus among the competition entries
that mentioned sound was on abating noise (69%), and not on
incorporating positive aspects of sound.
A tendency to rely on positive sounds: In an opposite tendency to the
defensive approach, it was found that some proposals (6.5%) only
focused on positive aspects of sound, while disregarding possibilities
to reduce noise levels. This tendency, which was also found in the
jury’s brief, was considered a misinterpretation of soundscape
thinking.
Discrepancies in communication of soundscape considerations:
Soundscape was rarely a prioritised aspect in the competition entries
submitted. Even in cases where efforts seemed to have been made to
improve the soundscape, this was not clearly communicated. These
discrepancies could be explained, for instance, by the visually
orientated tools and the potential gains in avoiding mentioning the
problematic soundscape.
Based on Paper II, there seems to be a need to increase priority and/or
knowledge about soundscape in landscape architectural practice in Sweden.
The soundscape approach could be a way to reach architects and planners, for
whom the science of acoustics has failed to raise interest. However, as Paper II
show, there is a risk of the soundscape approach being misused to avoid
addressing problems with noise. As a way to counteract this, it is suggested
that the model developed in Paper II could be used to ensure a comprehensive
(soundscape) approach to noise.
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3.3 Paper III: Urban soundscapes: A quasi-experiment in
landscape architecture
Figure 4. Image depicting the arbour that was the focus of the quasi-experiment in Paper III.
3.3.1 Background and aim
Paper III aimed to increase understanding of how the urban soundscape can be
considered and altered in design of outdoor space. The work centres around an
intervention – a small arbour that was built in a noise-exposed location in an
urban square in Malmö (Figure 4). The arbour walls were constructed from
noise screens that were covered with ivy. The arbour also contained a speaker
system.
The intervention was a result of a practice-based partnership project that
involved representatives from the park and road administration at the
municipality of Malmö and the acoustic consultant firm Ramböll. The design
intervention was discussed within an expert group consisting of landscape
architects, an acoustician, a traffic planner and a sociologist. Three consultants
were then appointed, together with another department at the municipality to
do the detailing and build the structure.
69
3.3.2 Methods
The project was designed as a quasi-experiment that centred around the arbour.
The arbour was evaluated through a mixed-method approach that included
measurements of sound pressure levels, observations and self-reports from (in
total) 205 visitors.
Visitors who agreed to participate in the study filled in a questionnaire, first
outside, and then inside, the arbour. Furthermore, the participants were divided
into two groups. The first group was not exposed to any extra sounds from the
speakers, while the second group was exposed to forest sounds (played back
inside the arbour). The responses to the questionnaire were analysed using
ordinal logistic regression. Nine of the participants also took part in semistructured interviews.
3.3.3 Results
The statistical analysis revealed that the arbour improved the soundscape. This
effect was further enhanced for the second group of participants (who were
exposed to forest sounds inside the arbour). The difference between the two
participant groups confirmed the importance of qualitative considerations in
design of soundscapes, and showed that an increase in sound pressure level
can, in fact, improve soundscape assessment, at least up to around 58 dBA.
In addition to the quantitative part of the study, qualitative material such as
interviews, observations and participants’ comments contributed an additional
understanding of how the arbour was experienced. In this part of the study,
variation in the city soundscape was identified as an important aspect to
consider in soundscape design, together with expectations on the sound
environment.
The qualitative material also increased understanding of how masking
strategies can be implemented successfully. In addition to sound pressure
levels and other physical characteristics of the sound sources, the relative
direction between masker and target sound was identified as an important
factor for consideration.
It was also found that the use of speaker sounds could be perceived as
irritating in some cases, but also as an exciting feature that could be related to
the notion of soft fascination (Kaplan & Kaplan, 1989). A number of general
improvements for the arbour were identified and described as the intervention
was evaluated.
70
3.3.4 Discussion and outcomes
Paper III increases understanding of how design of soundscapes can be
approached in landscape architectural practice. On a larger scale, variation in a
city’s soundscape was found to offer the possibility for inhabitants to choose
soundscape, based on cues such as preference and mood. As a contrast to a
bustling city, the need for contrasting tranquil space was identified. The
concept investigated in Paper III, with the relatively small arbour, could be
further investigated in the future, especially in relation to densification of
cities.
Expectation is another aspect raised in Paper III. Expectation has been
noted previously as a factor to consider in soundscape assessment (Brambilla
& Maffei, 2006). For instance, in urban environments sounds from traffic are
more likely to be accepted, or even appreciated (Anderson et al., 1983; Whyte,
1980). This is also confirmed in Paper III, where it is shown that the bustle of
the city could be regarded as a quality.
Finally, Paper III shows that the use of a comprehensive approach, in
which masking strategies are combined with noise abatement, is fruitful when
discussing soundscape applications. The use of masking strategies was found
to be effective at the given sound pressure level, i.e. 58 dBA. This supports a
claim made previously by Zhang and Kang (2007) that it is beneficial to work
with masking strategies up to 65-70 dBA, but that if sound levels exceed this
threshold, all sounds are disturbing.
3.4 Paper IV: Soundscape actions: A tool for noise
treatment based on three workshops in landscape
architecture
3.4.1 Background and aim
Paper IV is based on three workshops in landscape architecture that
incorporated soundscape as a way to address noise. The purpose was to
describe experiences from the workshops and structure the outcomes in a way
that would make them accessible to practitioners.
The workshops were conducted in different contexts and with different
combinations of participants. The first workshop was conducted in 2012 as part
of a partnership project (a continuation of the project described in Paper III).
This workshop involved landscape architects, acousticians and artists (see
Figure 5). The second workshop was carried out in 2015 as part of a practiceorientated research project at the woodland cemetery in Stockholm. This
71
workshop involved landscape architects, researchers in soundscape,
acousticians and experts in cemetery environments. The final workshop, held
in 2016, was part of a Master’s course in landscape architecture and all
participants were landscape architecture students.
Figure 5. One of the workshop groups in action developing ideas for soundscape improvement
(Paper IV).
3.4.2 Methods
The workshops were studied through an approach that made use of the model
introduced in Paper II. All proposals made by the workshop participants were
summarised in short keyword phrases that described the most essential aspects
of each proposal. All keyword summaries were then given one of three
positions in the model and were sorted so that similar proposals were clustered
together (see Figure 6). Once the clusters had been outlined, they were
described and each one was denoted a ‘soundscape action’.
3.4.3 Results
The analysis resulted in identification of 22 soundscape actions. The following
summary of the soundscape actions is structured based on the three categories
in the model that were used to identify them.
Soundscape actions related to the model’s first category were:
Compensation/variation, avoid unwanted sound, embrace unwanted sound.
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Soundscape actions related to the model’s second category were:
Vegetation for noise reduction, high noise screens, low noise screens, buildings
as screens, change topography, reduce source activity, abolish certain
functions, maintenance, absorbing qualities of materials.
Soundscape actions related to the model’s third category were: Auditory
masking, visual masking, materiality (water), materiality (vegetation),
materiality (walking), atmospheric design (loud-speaker based), sound
sculpture and urban furniture, biotope design, attract activities, resonance and
reflections.
Figure 6. Illustration of how clusters were formed to become ‘soundscape actions’ in Paper IV.
3.4.4 Discussion and outcomes
The work in Paper IV resulted in 22 soundscape actions, each of which
represents a concrete way in which soundscape thinking can be used to address
noise issues. An additional action, ‘Embrace wanted sounds’, was identified in
the discussion. This is included in the extended summary given in section 4.6,
making a total of 23 soundscape actions to date.
The methodology was grounded in landscape architectural practice, as it
was based on three workshops that included landscape architects, as well as
other professionals. The proposals varied to some extent depending on the
workshop context in which they were presented. This variation was considered
an asset and potential explanations are discussed in Paper IV in terms of
differences between the workshops.
73
The discussion covers practical applications, including the need for further
research in which the soundscape action is tested and evaluated in relation to
other available tools and situations. Such research could also look into the
structure of the tool, which could gain from being presented on a digital
platform that allows multiple tags.
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4
Discussion of results
This section summarises and discusses the results obtained in Papers I-IV in
relation to previous research and future work. The text is structured around a
number of themes identified in the thesis work process, which are used here to
collate results from the individual studies and to drive the discussion.
The first set of themes focuses on present practice and discusses how
landscape architects work with sound. Using this understanding as a
foundation, the discussion gradually moves on to deal with the topic of how
and why practice could improve its thinking on soundscape issues. This
involves discussions on strategies, tools and sonic experience.
4.1 Understanding soundscape thinking in landscape
architecture practice
Making general statements about how sound is treated in landscape
architecture practice is difficult. There are probably as many different ways to
understand and work with soundscape as there are landscape architects.
Nevertheless, some tendencies were identified in the thesis work. Some of
these tendencies seemingly contradict each other, indicating the existence of
overlapping understandings.
4.1.1 Increased interest in sound in landscape architecture: Influence
from the soundscape approach
There are good, interesting examples of the treatment of sound in
contemporary landscape architecture. Such examples are presented in this
thesis, e.g. in Paper II, where a design proposal called ‘Alice’ is identified and
described. In Paper I, the rehabilitation garden studied had been designed with
consideration for sensory experience of nature, including sound (although there
75
were problems with noise at the site). The review of seminal publications,
similarly, revealed a growing number of actual projects around the world in
which consideration of sound has played a significant role (although fewer of
these have actually been assessed and studied in an academic context). In
addition, the review of seminal publications indicated that there has been
increasing awareness about sound in the field in recent years.
This increased awareness about sound in contemporary landscape
architecture can partly be explained by the development of the soundscape
approach. The soundscape approach, in which the experience of sound (rather
than noise) is given a greater focus, seems to have helped increase interest in
sound among landscape architects. This was also one of the original intentions
with the soundscape approach, i.e. to raise the imagination in a way that
environmental noise management did not (Brown, 2010b; Schafer, 1994
[1977]). Soundscape thinking can, in this sense, open the way for landscape
architects to work with sound in new approaches.
This development is interesting, but it can potentially also be problematic as
there seems to be an understanding within practice that working with
soundscapes can be straightforward. Paley Park 8, for instance, even though it
has not been studied extensively, is commonly referred to in landscape
architecture publications as a successful example of how masking can be
incorporated in landscape design and how even a loud environment can be
made soothing by adding water sounds (see review in section 2.1.2). However,
as indicated in this thesis and other studies (Cerwén et al., 2016; Rådsten
Ekman, 2015; Brown & Rutherford, 1994), masking is not a straightforward
task, but depends on several different factors for successful implementation,
such as type of masking, type of environment, figure/ground relationships,
directions of sound sources, sound pressure levels and sonic characteristics.
There is also a risk, as shown in Paper II, of soundscape thinking being
used as a motive to disregard problems with noise. It is thus possible that
soundscape thinking, even if intended to improve the sound environment, may
in fact have the opposite effect if not implemented carefully. For instance,
masking should not be regarded as a simple ad hoc solution to allow
exploitation in noisy areas.
8
Paley Park is a pocket park in midtown Manhattan, opened in 1967 and designed by Zion
Breen Richardson Associates. It is known among other things for its waterfall, the sound of which
produces a masking effect in relation to the surrounding city (Whyte, 1980).
76
4.1.2 A hegemony of vision in landscape architecture? A nuanced
critique and a reliance on environmental noise management
As discussed previously in this thesis, landscape architecture and related
disciplines have been criticised for being ocularcentric in their approaches
(Pallasmaa, 2012 [1996]; Jakobsson, 2009; Hedfors, 2003; Lynch, 1976;
Rasmussen, 1964 [1959]). This criticism is directed particularly at the
modernistic tradition and its presumed failure to address sound and other
senses in a satisfactory manner. This thesis shows that, although there has been
an increased interest in sonic thinking in the field, some of this criticism is still
justified. This is evident from the review of seminal publications (see section
2.1.2) and the studies of contemporary practice, particularly Paper II. However,
while much of the earlier critique was categorical and failed to articulate more
specifically the ways in which consideration for sound was/is lacking, this
thesis contributes a nuanced understanding in this respect.
In the study of the architectural competition in Paper II, it was shown that
one-quarter of competition entries did not address sound at all. This was
noteworthy considering that there were severe problems with noise at the
competition site. This was taken to indicate that, in these cases, sound was
either not recognised as a high priority and/or that there was a reliance on
acousticians to deal with the noise in later phases. The remaining three-quarters
of entries addressed the problematic sound environment in their proposals. The
most typical way to do this was to propose screening (59%). It is argued in
Paper II that there was an overreliance on screening as a general and only
solution to abate noise. On the other hand, it was shown that relatively few of
the competition entries (20%) referred to localisation of functions as a way to
deal with noise. This was considered a remarkably low proportion given the
variation in sound pressure levels at the competition site, as well as the early
stage of the design process.
It was beyond the scope of Paper II to investigate in full the reasons for
these choices related to localisation of functions, but sound is clearly an
overlooked consideration. A related aspect was also identified in Paper I,
where the south-eastern parts of a rehabilitation garden were exposed to noise
coming from an adjacent motorway. Localisation of functions seems to be a
particularly overlooked aspect of soundscape design that should be raised in
practice. The comprehensive model proposed in Paper II could be a means to
do this (see section 4.5).
On a general level, Paper II indicates that there is scope to further integrate
knowledge on sound and acoustics within the discipline. There is a tendency to
either ignore problems with noise, or to depend on schematic solutions and
environmental noise management to deal with them.
77
Reliance on environmental noise management is not surprising considering
the fact that it is an established field occupied by specialists trained in
acoustics. Yet, whether acousticians are involved or not, landscape architects
take decisions every day that have an effect on the sonic environment. In this
respect, a basic understanding of acoustics seems valuable for the profession.
An increased understanding of acoustics would offer possibilities to design
with sound as part of visual aesthetics, as shown in Papers II-IV (cf. Hellström,
2016; Nilsson et al., 2015; HOSANNA, 2013; Åkerlöf et al., 1998).
If the acoustic perspective is considered too late, it may have negative
effects on the design process (Coelho, 2016). This is illustrated in Paper II by
the fact that, after the competition, the winning proposal had to be moved to
areas further from road infrastructure in order to ensure a purposeful sound
environment. Training in acoustics would ensure that landscape architects
could better communicate with acousticians and know when to involve them.
An important aspect in this context could be to examine how sound
pressure levels relate to environmental experience, as this could be an
additional way to link the disciplines. This thesis presents some investigations
into such links, e.g. it is shown in Paper III that masking strategies can be
effective at least to 58 dBA. In a study reported elsewhere (Cerwén et al.,
2016), the limit was extended to 64 dBA, coming close to Zhang and Kang’s
(2007) proposal of 65-70 dBA as an upper limit to work with masking
strategies. However, as discussed in Paper II, and also reported elsewhere
(Cerwén et al., 2016), tranquil qualities could be difficult to achieve at this
level (cf. Pheasant et al., 2008; Nilsson & Berglund, 2006). It seems feasible to
assume, therefore, that different types of sound pressure levels can be
associated with different environmental qualities or affordances (cf. Thibaud,
1998; Gibson, 1986). It could be fruitful in future work to develop a chart
where connections like those described here are summarised.
4.1.3 Shallow strategies: a call for a soundscape approach to noise
It seems that, even when sound is addressed within the field, there is scope to
improve the way in which the topic is approached. For instance, when sound is
mentioned, the mention tends to be limited to a short section in a publication or
a conceptual idea in a design proposal. Mentions of sound typically refer either
to the potential of sound or noise abatement. There are fewer examples of
combinations of these perspectives and approaches.
In the evaluation in Paper II, three basic categories were used as criteria. It
was found that combinations of these categories were unusual. Instead, there
was a strong tendency for competition entries to use only one of the categories
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(the most typical example being reduction of unwanted sounds, as in the use of
noise screens). This use of conceptual, limited or shallow approaches to abate
noise is also evident in the review of seminal publications.
It appears that soundscape thinking, where multiple aspects of the sound
environment are considered, is not yet integrated in practice. One reason for
this could be the limited number of previous applications and examples. Most
previous examples have tended to focus on noise reduction and, in some cases,
masking strategies. In this thesis, both strategies were combined in Paper III,
where a design intervention was built in an urban square. The assessment of
the intervention confirmed that the combination of strategies, as in a
soundscape approach to noise, was the most fruitful approach to enhance the
sonic environment. The project described in Paper III could therefore be used
as an example to stimulate interest further. In Paper II, a similar approach was
identified and referred to as a comprehensive strategy, when discussing the
proposal called ‘Alice’. Another example of a comprehensive strategy
previously mentioned in the thesis can be found in Sheaf square 9 in Sheffield,
UK. However, this site has not yet been assessed in research.
Landscape architects have several aspects besides sound that need to be
considered. This requires tools to aid consideration for sound in a
comprehensive manner. The comprehensive approach formed a starting point
in the development of such tools in Papers II and IV, as described and
discussed in sections 4.5 and 4.6.
4.2 Soundscape thinking in landscape architecture : A
relevant pursuit
This section discusses the relevance of soundscape thinking in landscape
architecture. More specifically, it discusses the contributions made in this
thesis to understanding the role of sound in environmental experience, in
particular in two studies based on a methodological approach that investigated
the role of sound in environmental experience (Papers I 10 and III).
Furthermore, using experiences drawn from all studies (Papers I-IV), it goes on
9
The “cutting edge sculpture” on Sheaf square in Sheffield is designed to work as a noise
screen, but it is also a water installation. In this way, noise from the road is reduced and masked
simultaneously. The sculpture was designed by Si Applied and Keiko Mukaide.
10
Paper I was based on interviews with patients suffering from stress-related mental disorders
and undergoing treatment in a nature-based rehabilitation garden. It was assumed that the findings
from this applied therapy situation can be useful to form an understanding of recuperation in other
situations as well.
79
to discuss connections between sound and landscape architecture that were
identified on a general level.
4.2.1 Sonic experience
Sound influences health, wellbeing and everyday experience (Meng & Kang,
2016; Preis et al., 2015; Basner et al., 2014). A review of the research situation
(see sections 1.2 and 1.3) revealed e.g. recent findings indicating a connection
between exposure to nature sounds and positive health effects (Annerstedt et
al., 2013; Alvarsson et al., 2010). This connection was confirmed in Paper I,
where experience of natural sounds seemed to be able to help patients
recuperate from mental illness through inducement of “soft fascination”
(Kaplan & Kaplan, 1989). Paper I also proposes that the interaction between
various sensory inputs could be important in inducing soft fascination. The
potential relationship between soft fascination and sound is also considered in
Paper III, where the discovery of hidden speakers raised interest, particularly
among children who visited the intervention. Fascination is one of four
elements in attention restoration theory (Kaplan, 1995), the other three being
extent, being away and compatibility.
The negative effects pertaining to noise exposure are well-established in
research (Basner et al., 2014). Papers I and III confirmed that technological
sounds are generally perceived as problematic. In Paper I, technological sounds
were exclusively perceived as negative and it was found that exposure could
hinder the rehabilitation process. The disturbance was found to be relative to
patients’ previous exposure.
In Paper III, a design intervention reduced noise from an adjacent street and
this was found to have a general positive effect on the soundscape. However, in
the same study it was found that noise could have positive effects in enhancing
urban qualities. This confirms previous observations by Whyte (1980) and
findings by Anderson (1983).
The role of sound in social interaction and behaviour is discussed in Paper
I. In that study, sounds from walking paths had a general positive effect, both
to give feedback on the subject’s own movement and as a warning signal of
other potentially unwanted people approaching. It was also found that the
attitudes to sounds from other humans varied depending on loudness, social
context and phase of treatment.
To conclude, this thesis work confirms previous findings on the influence
of sound and contributes a nuanced understanding regarding some of the
relationships between sounds, humans and environments. The role of sound in
environmental experience, together with the confirmed potential to influence
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the sound environment in landscape architecture, as illustrated in Paper III and
elaborated upon in Paper IV, motivates further investigations and
implementations in the field.
4.2.2 Sound and landscape architecture on a general level: Activities,
materiality and spatiality
This section draws on experiences from Papers I-IV to discuss connections
between sound and landscape architecture on a general level. In the papers,
three aspects seemed to recur: activities, materiality and spatiality. In what
follows, each of the three aspects is used as a vehicle to discuss the relationship
between sound, sonic experience and landscape architecture.
Activities
Discussions on activities in this thesis follow a distinction proposed in the
Swedish soundscape protocol, where sounds are divided, based on source type,
into natural, technological and human-induced sounds (Axelsson et al., 2010;
Nilsson & Berglund, 2006). Essentially, the thesis work confirms previous
findings pertaining to assessment of these categories, as described in section
4.2.1. It seems that a general strategy for landscape architecture could be to
stimulate natural sounds, while finding ways to abate technological sounds.
Much of the thesis work was concerned with identifying and discussing
concrete actions to achieve this (particularly Paper IV). Human sounds were
considered too, but were found to be more complicated to deal with in design
situations because: a) perceptions of these sounds are more varied, as indicated
in Paper I, and b) localisation of people is more difficult to control in a design
situation (but could be tied to certain characteristic locations, such as
playgrounds, cafés and markets).
It should be noted that the three sound source categories discussed here are
broad and each category covers a wide variety of sources. Moreover, in reallife situations, various combinations of sources are likely to occur. The
compatibility between different kinds of activities is dealt with to some extent
in the thesis, most typically in situations where masking strategies are
discussed, as in Paper III where forest sounds were used to shift the focus from
a road 11. In that particular case, it seemed that the proximity to the respective
sound source types could play a role in how they were assessed together.
Environmental sounds are in this sense related to gestalt psychology and the
11
In Paper III, forest sounds were transmitted by speakers to produce an effect of informational
masking (Moore, 2012).
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notion of figure and ground, as discussed by Hedfors (2003), Truax (2001
[1984]) and Schafer (1994 [1977]).
Such relationships seem to be important to consider when seeking to
understand masking strategies. For instance, masking could be problematic if
the masker and the target sounds are equally prominent, as this could cause
ambiguity. It seems that both visual and auditive cues could be important to
determine figure and ground. For instance, attention can be attracted by
characteristics of sound, as in a fluctuating water feature (cf. Rådsten Ekman,
2015). It has also been shown that visual information can be used to modulate
connections in the auditory system in order to change the perception of sounds
(Hunter et al., 2010). Visual cues could thus be used to make a water feature
seem more prominent, including from a sonic perspective. It seems reasonable
to assume that other sensory inputs could have similar effects.
Materiality
Materiality can be linked to a broad number of sensory and phenomenological
experiences, including vision and tactility. In terms of hearing, it seems
possible to discern three different ways in which sound relates to materials:
actively, interactively or passively. This division is based on the way in which
sound is affected, or activated, by a material. Each material can be activated in
more than one way; the distinction is thus not a means by which to classify
materials per se, but should rather be considered as a way to understand the
inherent possibilities in materials and the way they can be used.
Materials are acoustically active when they produce a sound, as in water
features, speakers or rustling vegetation. In active production of sound, the
main intention is not to involve visitors in the production of sound. Rather, the
materials produce sound independently.
The interactive acoustic characteristic of materials, on the other hand,
requires some sort of involvement from visitors to be activated. Examples of
acoustically interactive materials are gravel in paths (requires walking) or
interactive sound art installations that are triggered by the visitor. Other
examples of materials that can inspire interactivity are water mirrors or autumn
leaves lying on the ground. The role of acoustically interactive materials is
illustrated in Paper I, which found that the interaction with nature in a
rehabilitation garden could be improved by the use of walking materials which
produce sound when walked upon.
Passive characteristics refer to the passive acoustic qualities of a material
and the way a material responds when sounds are projected onto it (as in
reflection, absorption and/or transmission). The passive qualities of materials
can be important in abating noise, as in the use of absorbing vegetated soil in
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strategic positions (HOSANNA, 2013). Furthermore, different materials are
known to produce different ‘colourations’ to the sound that is reflected from
them, as experienced, for instance, in the warm atmospheric timbre of a log
cabin.
The sonic qualities of architectural spaces are dependent on material and
spatial qualities (Blesser & Salter, 2007; Pallasmaa, 2006; Zumthor, 2006;
Rasmussen, 1964 [1959]). In addition to sound, atmospheric qualities in
architectural spaces involve a number of other cues, including light and the
arrangement of objects within a space (Böhme, 2000). The relationship
between sound and architecture led the Swiss architect Peter Zumthor (2006) to
compare interior spaces to large instruments.
The tripartite way of considering materials, described above in terms of
acoustically active, interactive and passive qualities, relates to the distinction
made by Hedfors (2003) between landscape as a generator (cf. active material)
and landscape as a resonator (cf. passive material), but applies this distinction
to materiality and adds an additional interactive dimension.
Spatiality
Spatiality, like materiality, is a central concept in architectural disciplines.
Spatiality is used here to collect some of the findings in the thesis and position
these in relation to landscape architecture.
In architectural contexts, spatiality is perhaps most commonly associated
with physical delimitation of space, as experienced visually. Blesser and Salter
(2007) have shown that it is fruitful to consider space from a sonic perspective.
To facilitate discussions on sonic space, Blesser & Salter introduced concepts
such as acoustic arena 12 and acoustic horizon 13 .
The relationship between visual and auditory space seems to be of interest
for consideration in design situations. For instance, it is possible to seclude a
space visually, yet allow contact sonically. It seems relevant to have terms to
describe such connections. For vision, sight line is an established term in
architectural disciplines used to describe a visual connection to objects of
interest. An auditory counterpart seems relevant and a corresponding term for
such purposes in architectural disciplines could be sound line 14. The tension
12
The area in which a sonic event (target sound) can be heard.
Delineates the maximum audible distance to a sonic event.
14
Sound line is introduced here with the intention that it may be used within landscape
architecture and related disciplines. It can be used to emphasise a sonic connection to objects of
interest in the surrounding environment (as in hearing a waterfall on a distance). Visual
connection is not necessary to establish a sound line. The term auditory channel (Blesser &
Salter, 2007) is related but emphasises the listener and the social dimension more.
13
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between sound and vision is dealt with in Paper IV, where the notion of ‘visual
masking’ is discussed as a potential strategy to reduce impacts from noise.
Sounds are located in space in relation to each other and in relation to an
imagined listener. This thesis illustrates how such relationships are relevant to
consider in landscape architecture through a strategy denoted ‘localisation of
functions’ (Papers II and IV). A recurring consideration is the relative location
of unwanted sound sources (noise) and listening position. Localisation of
unwanted sounds is discussed in Papers I, II and IV, with the dominant strategy
being to ensure distance to the unwanted sound. In addition to distance, a
related strategy is to use positions shielded by noise through topography. In
Paper III, the relative directions of sound sources are discussed, as this was
identified as a potentially important aspect to consider when working with
masking strategies.
Shaping the landscape and physical space also means shaping the
prerequisites for sonic space. Buildings, topography and vegetation constitute
some examples. When it comes to noise treatment, screens have hitherto been
an important tool to control sonic space from unwanted sound. The use of
screens is discussed in Papers II-IV in terms of how they could be incorporated
in design solutions. In Paper III, noise screens were used to shape a small
room, which was then covered with ivy to produce a sense of an arbour. This is
one example of how consideration of sonic space can be integrated with the
visual shaping of landscapes.
4.3 Representation of soundscapes
As found in this thesis, representations of soundscapes in landscape
architecture projects can be divided broadly into visual, textual and auditory
representations (cf. section 2.3.2).
Visual representations of soundscape proved to be uncommon in the areas
of practice studied in the thesis. When visual representations were used to
depict sound, their use was mostly restricted to mapping of noise. Based on the
way landscape architects tend to work, i.e. through visual representations, this
is noteworthy. As illustrated in workshops with students reported by Fowler
(2013) and in other contexts (Aiello et al., 2016; Vogiatzis & Remy, 2014),
there is clearly potential to evolve the use of visual soundscape representations.
Such tools would be compatible with established (visual) forums to
communicate landscape architecture, such as magazines, posters and books.
This would be a major benefit, as landscape architects are already accustomed
to communicating with visual information.
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Most of the references to sonic experiences encountered during the studies
were conceived of in text. As expected, the character of the descriptions
covered a wide range, from the rich and almost poetic language used in the
literature by e.g. Spirn (1998), Halprin (1973 [1963]) and McHarg (1971
[1969]) to the rather limited descriptions based on conceptual words like
‘quiet’ and ‘tranquil’ found in several competition entries in Paper II.
A discrepancy in the communication of soundscapes was found in Paper II,
as the ‘quiet’ and ‘tranquil’ environments often lacked corresponding actions
in the design proposals. This reveals the limitations inherent in textual
representations and an arbitrary attitude to sound. A similar tendency to
describe sonic experiences, but not connect them with design actions, was
found in the review of the literature and in Paper I.
Auralisation of soundscapes, as in the simulation of sound environments in
virtual (auditory) reality, is not considered in Papers I-IV. This is related to the
fact that auralisation was not possible in most cases, due to restrictions in the
contexts studied. For instance, the competition in Paper II was restricted to
presentation on A1/A3 sheets, which is a common and established format in
landscape architecture contexts. This restriction is considered a finding in its
own right, as the established tools used in various contexts (i.e. visual in this
case) are likely to influence the resulting designs.
Drawing on Latour’s (1999) notion of “circulating reference”, Olwig (2004)
argues that the tools used in approaching “the real” (as in a scientific study or
in a landscape architecture project) influence the understanding of that
situation. Maps, perspectives and drawings are examples of representations that
are established as common tools in landscape architecture. Following Olwig’s
(2004) argumentation, and considering that tools in landscape architecture are
predominantly visual, it follows that visual aspects might be given more focus
in the design process than would be the case if the designer were working in
situ or with the aid of auralisation.
The notion of “circulating reference” could be extended to include contexts
where landscape architecture projects are discussed and evaluated, such as
conferences, posters, blogs, books, journals and competitions. Similarly to the
design situation, these are environments where predominantly visual
representations are used. In some of these contexts, it is possible to
complement sonic information digitally, as in online internet pages with sound
examples, embedded video or sound recordings.
In the not-so-distant future, it should also be possible to access auralisation
techniques as established working tools in the profession. Already today,
examples of programmes that can be used in real-time sketching exist (Marchal
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et al., 2016; Pelzer et al., 2014). Further development and establishment of
auralisation in practice would be a great benefit, as it would potentially be
possible to try different solutions and experience how these influence the
soundscape. This would provide great possibilities for landscape architects to
consider sound in earlier stages of the process. Furthermore, establishment of
auralisation would increase understanding among landscape architects about
the role soundscapes play in experience of landscapes.
Field recording is a related, but more accessible technique that can be used
to capture existing sound environments. Field recordings can be used as a
means to complement other forms of landscape representations and/or to
understand atmospheric nuances (Prior, 2017). This is useful in teaching
situations (Fowler, 2013). Field recordings can be used to discuss relationships
between landscape architecture and sound through comparison of different
scenarios, or to provide examples of projects and solutions (Cerwén, 2010b).
Textual references, as discussed in section 4.3, are an established way to
describe sound in landscape architecture practice. However, there seem to be
some discrepancies between textual references and actual design. In a previous
interview study conducted in France, it was found that urban planners were
“lacking a vocabulary for describing their expectations or even to take stock of
urban situations with regard to sound” (Raimbault & Dubois, 2005, 344). Part
of the problem was attributed to “a lack of consensual descriptions”. More
recent progress in the soundscape field has included a definition of soundscape
(ISO, 2014) and development of tools for discussing and representing sound
(Berglund et al., 2013; Hedfors & Howell, 2011). This development could
perhaps also be fuelled by a related discourse as found in human geography,
where it is referred to as non-representational (Thrift, 2007) or more-thanrepresentational theory (Lorimer, 2005). Inspiration from these related fields
could be used to improve representations of sound in landscape architecture.
4.4 Variation as an ideal soundscape
Much of the work pertaining to sound environments in the 20th century tended
to be normative in taking a clear stance against urban noise. This is the case in
acoustic ecology and in environmental noise management (cf. section 2.2.5).
Given the negative health effects and other problems associated with noise
exposure from modern infrastructure and machines, this is an understandable
position. However, such a normative standpoint fails to take account of the
qualities inherent in lively urban areas, where sounds that are arbitrarily
labelled as noise can play an important part in an active and stimulating
experience (Whyte, 1980). In Paper III this connection is confirmed, as it was
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found that visitors were willing both to accept and appreciate a certain amount
of urban noise.
However, it is also suggested in Paper III that stimulating experiences
should be counteracted with contrasting and relative quiet environments, as this
is another important quality. Similar findings are reported in Paper I, where it
was found that different needs and preferences among participants could be
accounted for by considering a variation in the soundscape. In a sense, a varied
soundscape could therefore be regarded as democratic, as it increases the
possibilities to choose. The notion of variation is also discussed in Papers II
and IV.
It has previously been suggested that city planning should consider the
possibility to ensure variation in sound environments, particularly emphasising
access to tranquil qualities. Southworth (1969, 67) mentions the possibility to
create “sound- and climate-controlled public oases in the center of the city”.
Hedfors (2003, 60), similarly, describes an auditory refuge “as a place which
offers another acoustic environment than that of the surroundings”. Hedfors
goes on to discuss distribution of refuges in spatial planning and suggests that
visitor access within 300 m (as in existing recommendations for green area
distribution) could be a relevant starting point for auditory refuges. Hällgren
(2012b) applies a phenomenological perspective when suggesting a connection
between variation and qualitative everyday experience, thus bringing variation
to a more detailed scale. More recently, Lacey (2016, 1) calls for what could be
described as an offensive strategy in suggesting “establishment of networks of
sonic ruptures throughout urban centres, to diversify sonic environments and
expand the possibility for creative encounter”.
Even though the approaches are different, variation is clearly a recurring
theme in research on soundscape. Backed by previous research, and supported
by findings in the present thesis, it seems feasible to recommend soundscape
variation as a strategy to consider as a complement to other aspects in city
planning. It would need to be coordinated somehow with other aspects, like
visual cues to ensure purposeful environments.
An important aspect seems to be to identify different kinds of possible
soundscape characteristics. Research thus far has shown that, on a general
level, soundscapes experienced as positive seem to be either tranquil
(calm/relaxing) or exciting (exciting/vibrant/dynamic) (Davies et al., 2013;
Axelsson et al., 2010; Kang, 2007). The distinction between tranquil and
exciting qualities in the soundscape was also a recurring theme in the thesis
work and thus seems like a fruitful starting point to consider variation. Exciting
qualities are acknowledged to be important, but the focus in the following is on
the tranquil dimension, as this seems to be the most pertinent quality to uphold.
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The EU (2002) directive on noise (END) is interesting in this context, as it
stipulates that member states should map and protect quiet areas. It seems that
this approach could be fruitful to ensure variation in soundscapes, particularly
in urban areas. The END has already led to a number of initiatives, such as
‘tranquillity trails’ in the UK, mapping of quiet areas in Oslo and ‘The Guide
to Silence’ in Stockholm. However, the END is rather vague in its formulation,
which has led to a number of different definitions, methods and applications in
member states (EEA, 2014).
It follows from the concept of quiet areas that sound pressure levels are
important to understand and implement such areas. However, definitions
depend on context (urban/rural) and member state and typically vary between
25 and 55 dBA (cf. EEA, 2014). For rural areas, the demands are generally
higher than for urban areas, where a certain amount of noise is expected (and
more easily accepted). In an extensive study of suburban green areas and city
parks, Nilsson and Berglund (2006) found that good soundscape quality can
only be assured at daytime sound pressure levels below 50dBA. However, they
also found that good soundscape quality in such contexts is not merely about
sound pressure level. It is also stated in the END (EU, 2002) that quiet areas is
not a question of absolute silence, but rather the (relative) absence of noise.
Absence of noise is beneficial, not only because noise can be disturbing in
itself, but also because it makes way for other more subtle sounds, like sounds
of nature, to emerge.
An important factor in the future would be to better understand ‘quiet areas’
in different contexts. For instance, it is possible that quietness in a pocket park
is different from quietness in an urban park. Whyte (1980) argues that one of
the benefits of Paley Park is the social seclusion generated by its rather
powerful waterfall (in addition to masking traffic sounds, the waterfall masks
the sounds of other people). This is related to the notion of social quietness
(Pálsdóttir et al., 2014), which is discussed in Paper I as an important quality to
recover from stress. In some cases, such as in proximity to health centres, areas
with a higher sound pressure level (for instance created by a fountain) could be
beneficial, as they could offer seclusion from other people. According to Gehl
(2006), communication difficulties start to occur at around 60 dBA and this
could be a useful starting point in investigating such effects. However, there
could be a fine balance here, as Zhang and Kang (2007) report that if the sound
pressure level rises above 65-70 dBA, masking sound itself starts to become
annoying.
In terms of spatial planning of quiet areas, it seems feasible, as Hedfors (2003)
discusses, to coordinate planning of soundscape variation with planning of
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green structure. Parks and other recreational areas are particularly sensitive to
noise disturbance, and relative quietness constitutes an important quality to
ensure tranquillity (Pheasant et al., 2008). In Sweden, the national board for
housing, building and planning recommends that dwellings have access to
green areas within 300 m and mentions relative silence in green areas as an
important consideration (NBHBP, 2007).
Moreover, it seems that active enforcement of quiet areas in practice could
be further elaborated in design solutions. Paper IV collates design strategies
that could be used for this purpose and the design intervention that was built
and studied in Paper III could be a valuable reference object when developing
quiet areas in urban situations, particularly in pocket parks and smaller areas.
In design situations, it could also be beneficial to consider variation from a
phenomenological perspective. For instance, in the Japanese garden Murin-an,
variation in the soundscape is used to counterpoint the visitor’s entrance. On
the outer side of the garden, there is a loud water feature. Upon entering the
garden the visitor passes through an opening in a wall. The sound of the water
is screened out by the wall, thus acting to make the experience of entering the
garden seem relatively quiet and tranquil. This effect corresponds to what
Augoyard & Torgue (2005) call the sonic effect “cut-out”.
4.5 Facilitating soundscape thinking: A soundscape
approach to noise
A starting point in the thesis work was that the most fruitful approach to
working with the sound environment would be to consider it from several
different perspectives. This was confirmed by the work described in Paper III,
which found that, in a noise-exposed context, the combination of noise
reduction and added sounds through speakers was more efficient than noise
reduction alone. This was called a soundscape approach to noise in the thesis.
There are different ways to describe or define such a comprehensive
approach. In the thesis, two different frameworks are used. In what follows,
each of these is described and then the two are related in a discussion.
4.5.1 Defensive, offensive and creative strategies
The first framework, used in Papers I and III, was originally proposed by
Pascal Amphoux (1993) and its three strategies are denoted by Hellström
(2003; 2002) as defensive, offensive and creative. Each of these strategies
represents a general attitude to the sound environment.
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The defensive attitude is the most well-established, corresponding to
environmental noise management and reduction of noise. The offensive attitude
is more concerned with what people want to hear and places more focus on
how wanted sounds can be stimulated. The creative strategy, which potentially
overlaps the other two, includes creative art and design interventions, as well
as increasing awareness of sound among citizens.
4.5.2 Introducing a model for comprehensive action: Localisation,
reduction and introduction
In Paper II, a new, more specific framework was introduced for the purpose of
evaluating a design competition. Amphoux’s (1993) division could not be used
in this context, particularly as the notion of a ‘creative’ strategy proved
difficult to assess for a large number of competition entries. Thus, a new
framework was introduced in the form of a model based on other research
(Brown & Muhar, 2004; Hedfors, 2003; Southworth, 1969). Similarly to
Amphoux’s (1993) approach, this model is based on three strategies or
categories; I) Localisation of functions, II) reduction of unwanted sounds and
III) Introduction of wanted sounds (see Figure 7).
Figure 7. The approach referred to here as a model for comprehensive action, which was used to
evaluate competition proposals in Paper II.
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Localisation of functions is the category that is most concerned with
strategic decisions and overall planning. It deals with how different functions
are located in space (and time), and focuses on compatibility between new and
existing functions. This typically entails considering the influence of unwanted
sound sources, and how noise can be avoided by ensuring distance and/or
identifying areas that are shielded by e.g. topography and buildings. However,
it can also be about identifying existing qualities, like a river, to localise
functions. The other two categories concern decisions that are taken when the
locations have been fixed and are more related to design decisions. Reduction
of unwanted sounds is concerned with how interventions in the landscape can
be used to reduce noise in a given area. Examples include screens,
topographical changes or application of acoustically appropriate materials.
Introduction of wanted sounds is about introducing or finding ways to
stimulate sounds that are considered wanted. Examples include water features,
sound art, gravel paths and strategies to attract singing birds.
4.5.3 Comparing two frameworks
The two frameworks described above are related: Not only do they share a
tripartite structure, but there is also some overlap within the structures.
Amphoux’s (1993) notion of a defensive strategy, for instance, is akin to
reduction of unwanted sounds, even if the abstraction levels are different.
Similarly, the notion of an offensive strategy is akin to introduction of wanted
sounds. In other words, both frameworks acknowledge problems and
possibilities as central factors. This is supported in previous discussions on
soundscape design (Brown & Muhar, 2004; Schafer, 1994 [1977]; Southworth,
1969).
The main contribution in the model for comprehensive action introduced in
Paper II is the category Localisation of functions. This category overlaps the
other two and was introduced as it seemed to represent a basic, yet overlooked,
consideration for practitioners. The findings in Papers I and II confirm that this
is a pertinent consideration that needs further attention.
Both approaches described – that of Amphoux (1993) and the new model in
Paper II – could be used to encourage comprehensive thinking on sound in
landscape architecture. Amphoux’s division is more general and abstract, while
the model for comprehensive action introduced in Paper II is more pragmatic
and action-orientated. In other words, they have different applications. It is
argued in Paper II that the model for comprehensive action could be used “both
for understanding and for evaluating approaches to soundscaping in landscape
design” (p. 19). The model is also used in Paper IV as a means to analyse and
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structure design proposals emanating from three workshops where an extended
tool denoted ‘soundscape action’ was formulated (see section 4.6).
4.6 Soundscape actions
A soundscape action could be described as an action that can be performed by
landscape architects and urban designers for the purpose of improving
soundscapes in outdoor environments, particularly in and around areas exposed
to noise. Altogether, 23 soundscape actions are described below (Figure 8) and
together can be regarded as a design tool. The soundscape actions can be used
as a dictionary to inspire ideas and/or as a way of structuring knowledge on the
current state-of-the-art.
Below, each soundscape action is summarised 15. For this purpose, the 23
soundscape actions are structured around three main categories; Localisation of
functions, Reduction of unwanted sounds and Introduction of wanted sounds. 16
This is then followed by a discussion on the development of the soundscape
action, how it can be applied and its relationship with other tools.
Figure 8. Overview of the 23 soundscape actions identified in this thesis
15
A more detailed description of each soundscape action (including ideas generated in three
workshops in landscape architecture) can be found in Paper IV.
16
This division is derived from the comprehensive action model introduced in Paper II (see
Figure 7), which was also used when the soundscape actions were developed in Paper IV.
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I) Localisation of functions
Compensation/variation
Strategic use of contrasting soundscapes can be employed as a way to enhance
their respective differences as qualities, such as making a tranquil area seem
relatively quiet in relation to a busy street. Variation is generally discussed in
terms of enforcing tranquil qualities, as in quiet areas (EU, 2002), quiet façade
(de Kluizenaar et al., 2011), auditory refuges (Hedfors, 2003) and tranquil
space (Pheasant et al., 2008). However, little has been done in terms of
investigating the potential for working the other way around (cf. Whyte, 1980).
Avoid unwanted sounds
This involves strategic localisation of sensitive functions in positions sheltered
from noise. Sheltered positions can be secured if there is sufficient distance to
the noise source or by making use of the ‘sound shadow’ from existing
structures like buildings and/or topography. Noise has been shown to have
negative effects on health (Basner et al., 2014), communication (Gehl, 2006),
sleep (WHO, 2009), acoustic comfort (Yang & Kang, 2005) and willingness to
help other people (Cohen & Spacapan, 1984). Furthermore, absence of noise
correlates with tranquillity (Pheasant et al., 2008), an important quality in
parks, pocket parks and housing areas.
Embrace unwanted sounds
To embrace unwanted sounds is to acknowledge (existing) noise as an urban
quality that may be suitable for certain functions, like markets. It has been
observed that an active soundscape can have positive effects in enhancing
urban situations and offering social seclusion (Whyte, 1980). Sounds that are
arbitrarily described as noise may therefore in some cases be perceived as part
of an urban quality (cf. Paper III and Hellström, 2003). Yet, as discussed in
Paper III, it is also important to ensure that some areas are tranquil (cf.
Compensation/variation).
Embrace wanted sounds
To embrace wanted sounds is to identify qualities that already exist in the
soundscape so that they can be used as a prerequisite to locate new functions.
For instance, a new café could be located near an existing fountain to make use
of the water sound as an atmospheric quality (cf. Alexander et al., 1977).
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II) Reduction of unwanted sounds
Vegetation for noise reduction
This concerns the role vegetation can play in some contexts to reduce noise.
The measurable effect of vegetation in reducing noise has been debated (Van
Renterghem et al., 2015), yet if the layer is thick and dense, the effect can be
substantial. The ground effect related to the soil substrate should be raised in
this context (HOSANNA, 2013), as well as visual screening (cf. visual
masking) and the sound of rustling leaves (cf. auditory masking and materiality
(vegetation)).
High noise screens
High noise screens are approximately 1.8 m and above. These screens should
be located as close to the source (or listener) as possible for optimal effect
(Forssén et al., 2015). The effect depends on a number of factors, where height
is the main determinant (HOSANNA, 2013). In addition to conventional usage,
high noise screens can be used in a creative manner, as part of urban design
solutions incorporating features like seating (Fusaro et al., 2017), water and/or
vegetation (cf. Paper III and Hellström et al., 2013).
Low noise screens
A low noise screen compensates for its lower height (up to around 1 m) by
increased proximity to the noise it is screening. The effect can be substantial in
some cases (Defrance et al., 2015), but there are practical issues like
maintenance and traffic safety to consider. Like high screens, low screens can
be combined with creative solutions that incorporate water and vegetation to
form part of an urban design solution.
Buildings as screens
Strategically located buildings can be used as less obvious, yet effective, noise
screens, also in combination with conventional screens. Besides the height of
the buildings, the shape, location and materials applied in the building are
important (Hellström et al., 2013). If the buildings are intended for housing,
care needs to be taken to avoid sleep disturbance (FHWA, 1976). Noise
exposure on one side of the building can be compensated for to some extent by
a quiet façade where bedrooms can be located (de Kluizenaar et al., 2011).
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Change topography
The shaping of the landscape topography can be used to form hills, berms or
strategically shielded valleys. Earth berms along major infrastructure constitute
a well-known application (MTH, 1997). The detailing of berms in terms of
shape and use of vegetation material can have a substantial effect on
performance (HOSANNA, 2013).
Reduce source activity
The reduction of source activity constitutes a broad number of measures that
are aimed to influence the way an activity is carried out, so that noise is
reduced. In this thesis work, this action was mostly concerned with reduction
of traffic speed. Two different approaches were discernible; enforcement of
rules (e.g. speed limits) and design solutions that affect certain behaviours (e.g.
reduced lane size and shared space solutions). In the latter approach, a parallel
can be drawn to the notion of environmental affordances (Gibson, 1986), a
term which has also been applied to sound environments (Thibaud, 1998).
Abolish certain functions
Abolition or complete transformation of functions that produce unwanted
sounds, like the transformation of a car road to a walking path, can be
considered. Such a development would seem likely in relation to densification
and sustainable development. If traffic roads are transformed into green paths,
this action would be related to biotope design and absorbing qualities of
materials.
Maintenance
Everyday maintenance of outdoor space can have negative influences on the
soundscape, particularly through use of machines with combustion engines.
Maintenance can be considered by landscape architects in maintenance plans,
but also in design solutions (Cerwén, 2017). For instance, a meadow is less
likely to result in noisy maintenance activities than a mown lawn. Maintenance
may contribute qualities in the soundscape, as when hand-driven tools are used
or when animals are involved.
Absorbing qualities of materials
The absorbing qualities of certain materials can be used, particularly in
conjunction with unwanted source activities like roads, to reduce the impact
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from the sound (cf. Forssén et al., 2015). An interesting and useful example is
vegetated soil, but there are also other strategies under development in
collaboration with acousticians (HOSANNA, 2013).
III) Introduction of wanted sounds
Auditory masking
Auditory masking is a phenomenon that occurs when a sound (masker sound)
influences the perception of another sound (target sound), so that the focus
shifts from the target to the masker sound. There are two general types of
auditory masking; energetic and informational (Moore, 2012). In energetic
masking, the target sound is rendered inaudible (or less loud). In informational
masking, both sounds are audible but the focus shifts towards the masker sound
(cf. visual masking). Masking is a complex phenomenon that depends on
several cues for successful implementation, including physical characteristics
of sound sources and their relative location in space (cf. Paper III). Zhang and
Kang (2007) suggest that it is not fruitful to use this strategy if the sound
pressure level exceeds 65-70 dBA. If the intention is to achieve tranquil
qualities, significantly lower levels than this seem preferable in most cases
(Pheasant et al., 2008; Nilsson & Berglund, 2006). A possible exception is
when tranquillity is associated with social seclusion, in which case it may be
desirable to have higher sound pressure levels 17 in order to obstruct
communication (Whyte, 1980).
Visual masking
The general idea in visual masking is that, by hiding the visibility of an
unwanted sound source, the focus can be shifted away from the noise, thus
reducing the negative impact. A typical application of visual masking is using
vegetation to hide a road, with the vegetation having multiple other effects as
well (cf. vegetation for noise reduction and materiality (vegetation)). The
appropriate application of visual masking has been debated and the usefulness
seems to be dependent on the situation. Botteldooren et al. (2016) suggest that
visual masking is a fruitful strategy as long as the noise is not too obvious,
whereas with obvious noise the illusion is more difficult to achieve.
17
According to Gehl (2006), communication with other people starts to become difficult at
around 60 dBA.
96
Materiality (water)
Water is a classical component in landscape design that can be used for multisensory effects. There are multiple possibilities to control the sound of water,
for instance in terms of location, timbre, strength and rhythm (Nikolajew,
2003; Halprin, 1973 [1963]). This could be one of the reasons why the sound
of water is commonly used as part of masking strategies (cf. auditory masking
and Rådsten Ekman, 2015; Galbrun & Ali, 2013; Brown & Rutherford, 1994).
Materiality (vegetation)
The sound of vegetation is perhaps most typically associated with leaves that
rustle in the wind; this particular effect can be enhanced through strategic
choice of species like poplar, bamboo and winter beech (Yang et al., 2016;
DeGroot, 2015). In Paper I, it is suggested that windy positions could be
chosen strategically to enhance the effect of rustling leaves (e.g. open fields,
mounds and wind tunnels). An additional benefit of vegetation in such
locations could be to reduce unwanted impacts of wind. Vegetation can be
associated with other sounds than rustling leaves, e.g. the sound of rain can be
enhanced by certain species such as bamboo, lotus and plantain (Yang et al.,
2016).
Materiality (walking)
Walking constitutes an interaction with the landscape that can be enhanced
through sonic feedback. This effect is discussed in Paper I, with gravel and (in
particular) wood being examples of materials that could give positive feedback.
Findings by Aletta et al. (2016a) confirm the impact of walking sounds on
soundscape quality, yet more research is needed to assess different kinds of
materials. Interestingly, it has been shown that soundscapes can influence
walking pace (Maculewicz et al., 2016).
Atmospheric design (loudspeaker-based)
Speakers are increasingly being used for various purposes in urban situations.
Sounds emitted through speakers can be used to design atmospheric qualities in
the environment. These atmospheric installations are not necessarily audible,
but aim to improve the architectonic qualities, particularly focusing on the
atmosphere. Two previous studies (Hellström et al., 2014; Billström &
Atienza, 2012) that assess users’ perceptions of such installations conclude that
there is potential to explore this approach further. There are also reports from
97
designers and artists sharing their experiences (Lacey, 2016; Dyrssen et al.,
2014; Hellström et al., 2011; Licitra et al., 2010).
Sound sculpture and urban furniture
Sound sculptures are installations that include sound as an important and
obvious part of an embellishment. The sound may be introduced through
speakers, or by other means. Sound sculptures can be merged with urban
furniture to include visitors as part of an interactive experience, or function as a
passive, yet clearly noticeable, embellishment. Musikiosk, an installation built
in a pocket park in Montreal and later evaluated in research, has been found to
enhance mood in visitors (Steele et al., 2016) and to have a positive effect on
social dynamics (Bild et al., 2016b). In Paper III, it was shown that a speaker
installation could be used to detract focus from noise.
Biotope design
Through consideration of biotopes, birds and other animals that contribute
sonic experiences can be attracted (Dawson, 1988). Hedfors (2003) introduced
the term “sonotope”, which could be applied to emphasise the sonic character
of biotopes. Songbirds are generally attracted by basic habitat features, such as
access to water, food and sheltering vegetation (Forman, 2014; DeGraaf,
2002). Vegetation and water can attract birds, and produce sound in other ways
(cf. materiality (vegetation and water)). To attract birds, vegetation should
ideally be dense, varied and in several layers. It could also be beneficial to
have older (and dead) vegetation, as there is a correlation between forest stand
maturity and bird species diversity (Gil-tena et al., 2009). Sounds of nature are
generally perceived of as positive (Axelsson et al., 2010) and bird song
diversity has been shown to enhance appreciation of urban landscapes further
(Hedblom et al., 2014).
Attract activities
Some areas intended for specific human activities, like cafés or playgrounds,
can generate a certain kind of soundscape. These soundscapes can offer
qualitative experiences even for people who are not actively involved, but in
the vicinity (cf. Embrace wanted sounds and Alexander et al., 1977).
98
Resonance and reflections
The acoustic qualities of materials and spaces can be used to enhance certain
wanted sounds through reflections and/or resonance effects. Such effects can
be used to emphasise qualities in the soundscape, such as water features,
meeting places and walking paths. The reflections may also constitute an
experience in their own right, as in a way to interact with the landscape
(Pallasmaa, 2012 [1996]; Blesser & Salter, 2007; Rasmussen, 1964 [1959]).
4.6.1 Soundscape actions: Future developments and positioning
The soundscape action model developed in Paper IV is a response to the need
for knowledge specifically tailored for landscape architects. In order to develop
and structure such knowledge, it was concluded that the most fruitful way
would be to work close with practice. Three workshops in landscape
architecture were arranged to accommodate this. The outcomes from the
workshops were analysed to identify recurring ideas and approaches. This was
considered as a good way to identify pertinent areas and ensure validity for
practitioners. A set of 22 areas was identified and denoted ‘soundscape
actions’. These were then used as a framework to discuss the current state-ofthe-art in research. As noted in Paper IV, an additional soundscape action,
‘Embrace wanted sounds’, was added in the above description, amounting to a
total of 23 actions.
In Paper IV, it is suggested that there are other possible ways in which the
soundscape actions could be sorted. For instance, it could be useful to
distinguish between major actions (like auditory masking, visual masking and
avoid unwanted sounds) and minor actions (like walking material, low noise
screens and attract activities). Future work should investigate the possibility to
develop an interactive version of the soundscape actions with overlapping tags
or filters to allow multiple options for sorting the actions. This could aid
identification of pertinent actions for designers. Such a digital platform would
also allow changes and updates as the field develops 18.
The soundscape action model is one of a growing number of tools for
architectural practices available today (see review in section 2.3.2).
Soundscape actions represent an approach that is based in landscape
architecture practice and focuses on improvement potential in the soundscape.
There is a relationship to the “sonic effect” (Augoyard & Torgue, 2005;
Augoyard & Torgue, 1995), which is a powerful tool offering a deep and
18
A digital platform for similar purposes has previously been developed by the thesis author
(Cerwén, 2010b). This platform could potentially be extended in future work to include
‘soundscape actions’.
99
comprehensive understanding of the sonic environment. The total of 82 sonic
effects cover a wide variety of aspects of the everyday experience of sound.
The focus of the sonic effect approach on sonic experience differs from that of
the soundscape action, which instead focuses on potential ways to change a
sound environment. The soundscape action is thought to be a more
straightforward approach to facilitate soundscape thinking for practitioners on
a general level.
Among previous tools, soundscape actions relate particularly to the toolbox
for acoustic design described by Hellström (Hellström, 2016; NBHBP, 2016;
City Sounds, 2013) and Lacey’s (2016; 2014) model for sonic rupture. The
latter, which was developed in artistic practice, is based on abstractions that
seem to be applicable on a general level, also for designers and architects. The
toolbox for acoustic design (City Sounds, 2013) places rather more focus on
building architecture and structures, while the soundscape action takes better
account of issues more typical for landscape architects, including system
thinking, activities and spatial localisation.
In future work, practitioners should be further involved to discuss
soundscape tools in terms of applicability in different contexts. Such studies
could be used to develop and position the concept of soundscape action further.
A possible combination or collection of different tools could be investigated.
100
5
Concluding remarks and future
prospects
The thesis was practice-orientated in its aim to facilitate soundscape thinking in
landscape architecture. It contributes knowledge and examples of how it is
possible to work with sound in landscape architecture, particularly focusing on
areas exposed to noise. The thesis also increases understanding of how
practising landscape architects actually work with sound and introduces
strategies and tools by which such considerations can be further enhanced.
The thesis illustrates that the potential to work with sound in landscape
architecture is yet to be fully recognised. The study of contemporary practice
reveals a rather shallow focus on sound and a reliance on environmental noise
management to deal with noise-exposed situations. Increased collaboration
between these professions would seem to be a good way forward. A
prerequisite would be to identify bridges between quantitative sound pressure
levels and qualitative design considerations (the thesis provides several
examples). There is also a need to raise examples and formulate knowledge
directed at landscape architecture. The thesis illustrates how landscape
architecture could approach problems with noise, e.g. through incorporation of
basic acoustic knowledge in design solutions and through masking strategies.
The thesis emphasises a comprehensive approach where problems and
possibilities in the soundscape are accounted for – also referred to as a
soundscape approach to noise. This is summarised in a tool based on three
different categories; localisation of functions, reduction of unwanted sounds
and introduction of wanted sounds. Each of these three categories represents a
general approach by which it is possible to achieve soundscape improvement,
and each of these three major aspects should be given consideration.
An extended version of the comprehensive tool is also introduced. This
tool, based on the same three basic categories, is denoted ‘soundscape action’
and includes a list of 23 concrete actions that could be taken to improve
101
soundscapes in noise-exposed situations. The soundscape actions were
formulated in a series of workshops that involved practising landscape
architects, artists, students, acousticians and other professionals. This increases
the relevance of the tool for landscape architects, as well as stimulating
collaboration between disciplines. In future work, the soundscape action should
be evaluated together with practitioners and possibly reformulated or optimised
for various contexts. In particular, it would be interesting to formulate a set of
actions that are not necessarily related to noise, but focus on the role of sound
as part of a phenomenological and interactive experience.
An important aspect of landscape architecture is how landscapes are
represented. This was not the major focus in the thesis, yet the development of
representations was identified as a strategy for further implementation of
soundscape thinking in the field. Technological developments have indeed
already created possibilities to represent sound in landscape projects in various
ways, for instance through auralisation techniques. Future work should
investigate possibilities for connecting auralisation techniques with the
soundscape action, to produce a platform for soundscape action sketching.
Another, possibly related, way to further develop the soundscape action
approach developed in the thesis would be to present the soundscape actions
interactively and online by use of overlapping tags to sort the outcomes in a
flexible and user-friendly manner.
In terms of appreciation of soundscapes, it was found that variation and
relationship between different kinds of soundscapes constitute a central aspect
that should be given further consideration in future work. The notion of ‘quiet
areas’ has attracted greater attention within the EU since the implementation of
the Environmental Noise Directive in 2002. As a concept, ‘quiet areas’ seems
to be a good way to enforce variation in soundscapes, particularly in urban
situations, where mapping and enforcement of quiet areas could be coordinated
with green plans.
The pronounced focus on sound in the thesis should not be considered as a
suggested paradigm, but rather as a means by which to inform landscape
architecture in general. While the thesis focuses on sound as an isolated
sensory input, the connection to the other senses is raised as significant. In
particular, a potential connection between sensory connectedness and health
benefits through the notion of ‘soft fascination’ was identified. This connection
should be studied in future work. For instance, it would be interesting to
compare natural and urban experiences in terms of sensory connectedness. A
health-promoting tradition called forest bathing (shinrin-yoku) in Japan could
be interesting in this context, particularly in relation to dense cities such as
Tokyo.
102
Contemporary landscape architecture is facing new challenges related to
increasing demands for sustainable development. Densification of cities can
have positive effects in stimulating urban life and activities. However,
densification could also be problematic if the higher density of activities causes
overstimulating environments. In particular, it seems reasonable to assume that
the need for contrasting and tranquil areas will increase as a result of
densification, making it pertinent to consider the soundscape in terms of
effective and strategic land use, as in localisation of functions.
This thesis illustrates some of the ways in which sustainable development
can have positive effects on the sound environment. For instance, the use of
vegetation (soil) in strategic locations can reduce the impact from unwanted
sounds. New kinds of urban furniture, as exemplified in the thesis, can be
designed in a way that is also beneficial acoustically. The increased use of
vegetation in cities can be a means to introduce and enhance wanted sounds to
promote health and environmental experience. Landscape architecture is a
profession of the times, and one in which the importance of green, blue and
environmentally friendly solutions can be accommodated. Soundscape thinking
adds an additional perspective to take account for.
Other related changes in society, such as increased use of electric cars and
bicycles, might well alter the prerequisites for dealing with soundscapes in
landscape architecture in the future. If traffic noise is reduced, this would
surely change the character of cities, for better or in some cases perhaps for
worse.
The intention with the present thesis was not to introduce a static set of
understandings for sonic considerations in cities, but rather to stimulate
soundscape thinking in the field. It was decided that the best situation to
position this undertaking would be to address an issue that is already
considered relevant – noise. Hopefully, the thesis work will stimulate
soundscape thinking, not only about noise, but also beyond.
In the beginning of this thesis, an interesting metaphor originally proposed by
the Canadian composer Murray Schafer, in which the sound environment is
likened to a continuously ongoing musical orchestra, was paraphrased.
Similarly to an orchestra, the soundscape has the potential to be subtle or
intense.
These qualities cannot co-exist, but the variation or tension between these
states is often what constitutes the essence of an experience.
103
Acknowledgements
Looking back on these last few years of working with this thesis, I have mixed
emotions. On the one hand, it is satisfactory to finish a great undertaking. On
the other hand, there are many things I will miss, such as the freedom
associated with writing and the possibility to combine travel and work. Most of
all, however, I will miss the people involved in the project. I would like to take
the opportunity here to thank some of the many people who were involved in,
or associated with, the project.
First of all, I would like to extend my gratitude to my supervisors. My main
supervisor, Carola Wingren, thank you for being a constant inspiration and
support throughout this long project. Your experience from both academia and
professional work was an invaluable asset, as was your encouraging spirit.
Thank you so much for sharing this and for being there. Mattias Qviström,
thank you for always being ready to provide valuable, stringent and insightful
comments. I highly value your knowledge in landscape research and appreciate
your strategic thinking. Jacob Kreutzfeldt, thank you for your engaged readings
and wise comments. I highly value your knowledge in sound studies. I am also
grateful for your reading as opponent in the half-time seminar. In addition, I
would like to thank Jan-Eric Englund for always being ready to discuss
statistical problems with great enthusiasm.
Furthermore, I want to thank Björn Hellström and Mats Lieberg for
supporting my early aspirations to become involved in research. The think tank
Movium was important in the beginning too, particularly Titti Olsson; thank
you for realising the subject’s potential and for supporting early initiatives. A
Movium partnership project entitled ‘Soundscape Malmö’ subsequently played
an important part in the thesis. This project would not have been possible
without Mats Lieberg, Sten Göransson, Ylva Pålstam, Anders Larsson and
Carola Wingren.
During my work, I had the opportunity to collaborate with great colleagues
in a number of projects. In particular, I would like to acknowledge the
104
following people: Eja Pedersen, Anna María Pálsdóttir, Anna Petersson, Frans
Mossberg, Erik Skärbäck, Maria Liljas, Eva Reimers, Mika Wendy Ogawa,
Martin Tunbjörk, Fredrik Jergmo, Märit Jansson and Eva Kristensson.
The importance of a good working atmosphere cannot be underestimated. I
want to acknowledge all the support from co-workers, students and fellow PhD
candidates in and around the Alnarp Campus. Fellow PhD students Johan
Pihel, Emma Paulsson, Jesper Magnusson, Paulina Prieto de La Fuente, Sandra
Kopljar, Marwa Al Khalidi, Åsa Stjerna, Nina Hällgren, Xiujuan Qiao, Mark
Wales, Måns Norlin and Fengping Yang. Roommates; Stina Bodelius, Erik
Fälth and Cheng Chang. For early inspiration: Per Hedfors, Björn Eriksson, Pär
Gustafsson and Ann Bergsjö. Encouraging and helpful people: Jitka Svensson,
Anna Peterson, Helena Mellqvist, Linnéa Lindström and Christel Lindgren.
Discussions: Kajsa Lawaczeck Körner, Jonathan Stoltz, Peter Dacke and Mike
Friesen. I would also like to acknowledge the library personnel in Alnarp and
the administration. Thank you all for being there.
Essentially, the thesis work concerns understanding the relationship
between people and sound. It goes without saying that the participation of
people – whether everyday visitors or designers – was important. I would like
to acknowledge everyone who contributed their time to provide empirical
material. In particular, I would like to thank all participants in the three
workshops that would become the foundation for Paper IV.
The thesis has been scrutinised by a number of people in different phases.
My supervisors played the most important role, but there are others that should
be acknowledged. Thanks to: Ricardo Atienza, for a great reading and
discussion in the final seminar; Eivor Bucht and Åsa Ode Sang, for reading the
thesis in its final stages and for making valuable suggestions for its
improvement; Vera Vicenzotti, Matilda Van Den Bosch, Lisa Diedrich and
Anna Jakobsson, for comments along the way; Mary McAfee, for language
checks on Paper I, Paper IV and this thesis essay and Graham Bowers, for
language checks on Papers II and III.
During periods of writing, I have found it useful to travel. Not only has it
been inspiring to visit new places with new soundscapes, but at times it has
also been a necessary means by which to find writing time. I would like to
thank: Gini Lee and Ray Green at the University of Melbourne, for inviting our
group of three Swedish PhD students in 2011 and for arranging a workshop
together with Mats Lieberg to explore urban life in Melbourne; Anthony
Magen with the RMIT in Melbourne, for arranging a soundscape seminar with
other researchers in the field; Eleni Gultidou, Elisabeth Gullberg Kaidi and
Stella Vakipoulou at the Swedish Kavalla house in Greece, for hosting two
productive and enjoyable visits in 2014 and 2015 where I felt very welcome;
105
Magnus Johansson, for a writing spree at Malmö University; Lars Johansson
and Per Berg, for numerous stays at SLU in Ultuna; Isami Kinoshita at Chiba
University in Tokyo, for your warm welcome and generous sharing of
knowledge – the five months I spent in the spatial planning lab in 2015 were
truly memorable, resulting in some great memories and many friends; Keiko
Torigoe and Masafumi Komatsu, for taking the time to meet and to share your
knowledge on Japanese soundscapes; and Anthony Pecqueux, Jean-Paul
Thibaud and Françoise Cholat at the research laboratory CRESSON in
Grenoble, for making possible a six-week inspiring writing spree.
This thesis work was funded by different projects, the major contributor
being the Swedish Research Council, FORMAS. In addition, the following
organisations provided funding: SLU, VINNOVA, Movium (SLU) and The
Sound Environment Centre (Lund University). My travels were supported by
grants from the following generous trusts: The SLU/LTJ Faculty Fund for
Internationalisation, The Royal Swedish Academy of Agriculture and
Forestry’s (KSLA) fund for travel grants and the SLU Fund for
Internationalisation.
I would also like to take the opportunity to thank Fudoushin Karate Do in
Malmö, particularly Milo Bajraktari and Igor Ardoris for inspirational training
that was essential to balance the thesis work.
Finally, and most importantly, my family and closest friends: thank you.
106
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Acta Universitatis Agriculturae Sueciae
Doctoral Thesis No. 2017:91
This thesis is about sound in landscape architecture. The soundscape
concept is used to emphasise the experience of sound and discuss
design applications, particularly in noise-exposed situations. A set of
strategies and tools for the profession is introduced as a soundscape
approach to noise, where problems and possibilities are accounted
for. This approach is exemplified in a reference project that was built
and evaluated as part of the thesis.
Gunnar Cerwén received his post graduate education at the
Department of Landscape Architecture, Planning and Management,
SLU, Alnarp. He received his degree of Master of Science in
Landscape Architecture at the Swedish University of Agricultural
Science.
Acta Universitatis Agriculturae Sueciae presents doctoral theses from
the Swedish University of Agricultural Sciences (SLU).
SLU generates knowledge for the sustainable use of biological natural
resources. Research, education, extension, as well as environmental
monitoring and assessment are used to achieve this goal.
Online publication of thesis summary: http://pub.epsilon.slu.se/
ISSN 1652-6880
ISBN (print version) 978- 91-7760-072-5
ISBN (electronic version) 978- 91-7760-073-2