Physics of Voice Production

Mechanisms of phonation

Source-tract interaction

Glottal flow

Effects of anisotropy

Biomechanics of vocal folds

Neuromuscular control of voice

Production and perception

Mechanical models of voice production

Computational models of voice production

Source-tract interaction: vocal fold vibration under the influence of acoustic loading

In addition to the near-field fluid-structure interaction within the glottis, vocal fold vibration is also subject to the influence of sub- and supraglottal acoustics. Using a self-oscillating physical model of the vocal folds, we systematically investigated such source-tract coupling for a large range of source/tract conditions. We showed that, for a stiff vocal fold model, self-oscillation of the vocal folds occurred only when the vocal fold vibration synchronized to either a subglottal or supraglottal resonance (Zhang et al., 2006a, 2006b). For a more general case, when vocal fold stiffness was decreased, the strength of the near-field fluid-structure interaction increased and the model self-oscillated in an aerodynamically drive mode at short tracheal tubes with minimal acoustic influence (Zhang et al., 2009). However, the vocal fold vibration transitioned from aerodynamically-driven to acoustically-driven vibration when one of the subglottal resonance frequencies approximated one of the natural frequencies of the vocal folds. In this region, strong superior-inferior vibrations were observed, the phonation threshold pressure was significantly reduced, and the phonation onset frequency was heavily influenced by the dominant acoustic resonance. For acoustically-driven phonation, a compliant subglottal system always lowered phonation threshold. However, an inertive vocal tract could either increase or decrease phonation threshold pressure, depending on the phonation frequency (Zhang et al., 2009).

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