Seiji Adachi
ATR Human Information Processing Res. Labs., 2-2 Hikaridai, Seika-cho, Soraku-gun, Kyoto, 619-02 Japan
Sound production in brass instruments has been formulated physically, including two different models of lip vibration; the perpendicular model, where lips strike laterally to the direction of the air flow, and the ``swinging door'' model, where lips execute outwardly rolling motion. The above formulation was used to carry out time-domain simulation. As a result, self-excitation of the brass instrument was found to be possible with both of these lip models. By changing the lip eigenfrequency, sustained oscillations near at least the first through the eighth resonant impedance peaks of the instrument were realized. The simulated sound was shown to have variety in the harmonic structure accompanied with pitch and loudness variations as is seen in sound the natural brass instruments produce. Unusual regimes of oscillation were also obtained; the pedal tone, whose fundamental does not participate in its sound production, a tone octave below the third impedance peak, whose odd harmonics do not contribute to the regime of oscillation, and a multiphonic, which is an oscillation perceived having two fundamentals simultaneously.