ABSTRACT
The input impedance of woodwind instruments is characterized by at least two bands due to the lattice of open toneholes, a stop band at low frequencies, and a pass band at higher frequencies where the acoustic energy is able to propagate past the first open tonehole and into the lattice. The cutoff frequency that separates these two bands is an approximate value that is determined by the geometry of the lattice of open toneholes. It is expected that the frequency at which the stop band transitions to the pass band affects the sound produced by the instrument, but it is not known how this frequency affects the competition between self-sustained oscillation and radiation. A simplified model of a clarinet-like resonator is conceived such that the first input impedance peak and the cutoff frequency can be independently chosen. Experimental prototypes are built and the measured impedance of these prototypes is compared with the simulations. Resonators with very similar low frequency behavior but very different cutoff frequencies are then compared using digital synthesis to evaluate the influence of the cutoff frequency on sound production. The cutoff frequency impacts the synthesized pressure and acoustic volume velocity in the mouthpiece, particularly regarding the spectral content at high frequencies.
