Mode coupling in the sound generation in wind instruments

摘要

The Fourier components generated by the non-linear excitation process are coupled to the acoustic modes of the pipe (and to those of the vocal tract). At low amplitudes the fundamental determines the frequency of the played note; at higher amplitudes higher modes are active, sometimes leading to unexpected occurrences. For example, for certain changes in fingerings on a woodwind the playing frequency may go up while the first peak of the input impedance goes down. This can be observed for fork fingerings. Similar effects can be expected in flaring horns and bends, where resonances in transverse direction can occur. In this paper some effects on woodwinds are studied; blowing observations are verified by time domain simulations.