First International Conference on Spoken Language Processing (ICSLP 90)
In this paper the characteristics of sound pressure distribution in the vocal tract are described on the basis of acoustic measurement. The measurement was performed with plaster replicas of the oral cavity. The validity of plane wave propagation is examined from the measured spatial distribution of the amplitude and phase of sound pressure for pure tone. It is shown that at certain frequencies, there exist points where sound pressure is absolutely zero, with the phase spatially circulating around them. A simple model is considered to explain this phenomenon. And up to about 4kHz except at these certain frequencies, the wave front is almost 1-dimensional though an amplitude gradient can be seen in the vertical direction. This paper also presents the characteristics of particle trajectories and of sound intensity fields.
Bibliographic reference. Motoki, Kunitoshi / Miki, Nobuhiro / Nagai, Nobuo (1990): "Measurement of sound wave characteristics in the vocal tract", In ICSLP-1990, 433-436.