Papers by Jean-Pierre Dalmont
Modern Acoustics and Signal Processing, 2016
The Journal of the Acoustical Society of America, 2015
When designing a wind instrument such as a clarinet, it can be useful to be able to predict the p... more When designing a wind instrument such as a clarinet, it can be useful to be able to predict the playing frequencies. This paper presents an analytical method to deduce these playing frequencies using the input impedance curve. Specifically there are two control parameters that have a significant influence on the playing frequency, the blowing pressure and reed opening. Four effects are known to alter the playing frequency and are examined separately: the flow rate due to the reed motion, the reed dynamics, the inharmonicity of the resonator, and the temperature gradient within the clarinet. The resulting playing frequencies for the first register of a particular professional level clarinet are found using the analytical formulas presented in this paper. The analytical predictions are then compared to numerically simulated results to validate the prediction accuracy. The main conclusion is that in general the playing frequency decreases above the oscillation threshold because of inha...
When blowing a wind instrument, the sound level is limited by the fact that when the blowing pres... more When blowing a wind instrument, the sound level is limited by the fact that when the blowing pressure increases the level also increases until a maximum beyond which the reed closes suddenly. Time domain simulations and experiments using an artificial blowing machine are used to demonstrate that losses are responsible for this phenomenon. Due to losses the pressure in the mouthpiece becomes too low to ensure the reopening of the reed. It is shown that, in the case of conical instruments, the same mechanism is responsible for the bifurcation to unusual modes such as the inverted Helmholtz motion.
Non intrusive measurement of a sinusoidal acoustic velocity in a mean movement of fluid is of int... more Non intrusive measurement of a sinusoidal acoustic velocity in a mean movement of fluid is of interest for number of practical application. Although signal processing techniques dedicated to Laser Doppler Velocimetry have been recently developed in order to measure sinusoidal acoustic velocities without flow in a large domain of magnitude and frequency (e.g. Valière et al., 2000), these techniques are not adapted in the presence of a mean flow because of the too short bursts duration and of the presence of turbulence, viewed as an additional high magnitude noise. A new method of signal processing, called 'perio-correlation' is proposed for evaluating sinusoidal acoustic velocity in the presence of mean flow. This short commu nication presents the results of an experiment conceived in collaboration between three laboratories First LDV measurements of acoustic velocity, and microphonic estimate of this velocity are compared.
Acta Acustica united with Acustica
ABSTRACT
Acta Acustica united with Acustica
ABSTRACT
When a clarinet with a fixed embouchure is blown, the oscillation starts for a given pressure and... more When a clarinet with a fixed embouchure is blown, the oscillation starts for a given pressure and stops for another pressure. Using the "simplest possible" model these pressures can be determined analytically. The analysis emphasises the influence of two physical parameters: the minimum pressure difference which closes the reed channel and a parameter proportional to the input impedance of the tube at resonance and to the maximum volume flow of the non linear characteristics. Depending on the value of this last parameter different bifurcation schemes are found.
Acta Acustica united with Acustica
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Papers by Jean-Pierre Dalmont