Effects of Soft-Wall Vibration and Radiation in a Dynamic Model of the Vocal Cords and Vocal Tract
K. Ishizaka, K. L. Shipley, James L. Flanagan · The Journal of the Acoustical Society of America · 1974
At the previous meeting of the Society, we described a computer model of the vocal cords and vocal tract system in which dynamic, physiologically based control functions accomplish speech synthesis [J. L. Flanagan, K. Ishizaka, and K. Shipley, “Dynamic Control of a Computer Model of the Vocal Cords,” J. Acoust. Soc. Am. 54, 319(A) (1973)]. The model has been extended to include the effects of vibration and radiation of the soft walls of the vocal tract. The influence of yielding walls upon the mode structure (formants) of the vocal system, upon the cord-tract acoustic interaction, and upon sound output during total occlusion is studied and reported. Articulatory dynamics of an intervocalic, voiced labial stop are used as a vehicle to expose the detailed behavior of the model. During occulsion, wall yielding is shown to contribute to sustenance of voicing, and wall radiation accounts for sound output. A computer movie film, generated at a slow-motion rate of 100 times real time, illustrates the coordinated interplay of cord and tract motion.