Model of Larynx Activity during Phonation

With the steady-state measurements made by van den Berg, et al. [J. van den Berg, J. T. Zantema, and P. Doornebal, Jr., “On the Air Resistance and Bernoulli Effect of the Human Larynx,” J. Acoust. Soc. Am. 29, 626–631 (1957)] as a basis, a quasistatic model of larynx activity during phonation has been developed. A computer simulation of this larynx model in conjunction with models of the vocal and subglottal tracts permits calculation of the various air-flow and pressure waveforms associated with the vocal-cord operation. Results of the simulation as they pertain to (1) correspondence with actual experiments, (2) physiological control of pitch, and (3) vocal source-vocal tract interaction are presented. The air-flow per cycle corresponds with average pressure and flow measurements made on singers and the waveforms and spectra are of the same forms as those obtained by inverse filtering. Source-tract interaction appears to be minimal. [Work supported in part by the National Institutes of Health, Public Health Service, U. S. Department of Health, Education, and Welfare, by the U. S. Air Force Cambridge Research Laboratories, OAR, by Project MAC, an MIT research program sponsored by the U. S. Department of Defense.]