Aix Marseille Univ, CNRS, Centrale Marseille, LMA, UMR 7031, Marseille
The impedance cutoff frequency due to the network of open toneholes is a well-known characteristic of woodwind instruments. Benade remarks that the frequency at which cutoff occurs is strongly related to the sound of an instrument and that it correlates to the adjectives musicians use to describe the character of a given instrument. However, it is not known how the cutoff frequency impacts the competition between the energy that facilitates the auto-oscillation of the reed and the energy that is radiated from the resonator. To evaluate the effects on sound production and radiation, simplified resonators with the same first impedance peak frequency, but different cutoff frequencies, are conceived and experimentally verified. It is found that both a rigorous geometrical and acoustic regularity result in a very strong cutoff behavior. Next, digital synthesis is used to simulate the pressure and velocity waveforms within the mouthpiece of resonators with different cutoff frequencies. Spectral characteristics of the resulting waveforms can be used to quantify how the cutoff frequency affects sound production.
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