ATR Human Information Processing Res. Labs., 2-2 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-02, Japan
Brass sound simulation is carried out with the use of a two-dimensional lip vibration model, where lips execute both rolling and reciprocating motions. This model allows lips to operate on both the lower and higher frequency sides of the air-column resonance frequencies. Oscillations generated by the total sound production system are on both the lower and higher frequency sides in the first and second resonance modes, while in the higher modes they are realized only on the lower side. The harmonic series selected from these oscillations in the second and higher modes to achieve the optimum pitch turns out to comprise an oscillation on the higher side of the second resonance frequency and oscillations on the lower sides of the higher resonance frequencies. This result closely matches the transition of lip vibration states from the outward-striking vibration at the second mode (i.e., the lowest mode among the ones used musically) to the vocal-cord-like vibration at the higher modes, which is observed in the simultaneous measurement [S. Yoshikawa, submitted to J. Acoust. Soc. Am.] of mouthpiece pressure and lip vibration.