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Naissance des oscillations dans les instruments de type clarinette à paramètre de contrôle variable

Abstract : The research presented in this thesis is a contribution to the study of attack transients in clarinet-like instruments. The main objective is to understand the behavior of the instrument when the mouth pressure of the musician is increased slowly through time at a constant rate. Although previous research proves that oscillations can appear at a value of the mouth pressure corresponding to 1/3 of the pressure needed to close the reed (the static oscillation threshold), numerical simulations and in vitro experiments show that for gradual increases of the mouth pressure, the audible sound generally appears when mouth pressure reaches a much higher value, called the dynamic oscillation threshold. This phenomenon is referred to as bifurcation delay in this work. A major part of this work follows an analytical approach, using the foundations of dynamic bifurcation theory to study the bifurcation delay in a simple and well known clarinet model (the "Raman" model). The properties of the dynamic oscillation threshold are related to indicators of the time variation of the mouth pressure such as its initial value and its slope. One of the remarkable features of the bifurcation delay is its strong dependence on noise, including that arising from round-off errors of the computer. The properties of the dynamic threshold are different according to whether the noise can be ignored or not. Additionally, an artificial mouth is used on a clarinet-like instrument to show that the bifurcation delay is not only a numerical phenomenon. Experimental observations performed on a clarinet-like instrument blown by an artificial mouth prove that bifurcation delay exists not only on numerical simulations, but also on real-life systems. These observations show that the properties of the bifurcation delay observed in low-precision simulations are similar to experimental ones.
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https://tel.archives-ouvertes.fr/tel-00877550
Contributor : Baptiste Bergeot Connect in order to contact the contributor
Submitted on : Tuesday, November 25, 2014 - 10:10:06 PM
Last modification on : Tuesday, October 19, 2021 - 10:59:09 PM
Long-term archiving on: : Friday, April 14, 2017 - 8:50:01 PM

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  • HAL Id : tel-00877550, version 3

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Baptiste Bergeot. Naissance des oscillations dans les instruments de type clarinette à paramètre de contrôle variable. Acoustique [physics.class-ph]. Université du Maine, 2013. Français. ⟨tel-00877550v3⟩

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