Self-oscillating source for vocal-tract synthesizers

Abstract

Absiraci-A self-oscillating model of the human vocal cords is derived and simulated on a digital computer. The model is used as a source of excitation for a vocal-tract synthesizer, also programmed on the computer. Synthetic speech from the simulation is used to study the influence of glottal parameters upon signal features. The cord model produces glottal volume velocity functions which reflect the acoustic interaction between source and tract. Voice pitch and irregularities in excitation are generated intrinsically from specification of subglottal pressure, cord tension, and tract configuration. Pitch produced by the cord model is a monotone increasing function of subglottal pressure and tension. Mean air flow and glottal duty factor depend upon a combination of parameters, but primarily upon the properties of the contacting surfaces during cord closure.

Vocal tract resonances in speech, singing, and playing musical instruments

“…Conversely, a woodwind reed is a "striking inwards" valve. Since then, a number of researchers have addressed the general problem of how such valves convert direct current (dc) flow into alternating current (ac) flow (Flanagan and Landgraf, 1968;Fletcher, 1979;Elliot and Bowsher, 1982). Fletcher (1993) develops a simple but general model to explain the interaction of a linear oscillator with this nonlinear pressure term to explain several features of valveresonator interaction and also includes a "striking sideways" valve, which opens due to pressure excess on either side.…”

An overview of the physiology, physics and modeling of the sound source for vowels.

“…The effect of inertial loading by the vocal tract was demonstrated in an early model [15] in which the vocal fold tissue (of either the right or left side) was lumped into a single mass ( Fig. 6) and allowed to have only lateral displacement.…”

“…The one-mass model [15] of the vocal folds. To make efficient use of space, the spring and damping elements have been lumped together in a single symbol.…”

“…While the one-mass model is generally not sufficient for research purposes, it is a useful instructive tool for learning some of the fundamental principles of self-sustained oscillation [3]. Shortly after the introduction of the one-mass model [15] a slightly more complex version was proposed that represented a single vocal fold by two-masses in the coronal (vertical) dimension [12,17] (Fig. 7).…”

Computational modeling of phonatory dynamics in a tubular three-dimensional model of the human larynx

“…Computational modeling has been used to study phonation from the very early stages of research in this arena (Flanagan and Landgraf, 1968). In the early models, the VFs were represented by a small number of lumped-elements and the flow was usually described by the Bernoulli equation.…”