Biomechanical modeling of register transitions and the role of vocal tract resonators

J Acoust Soc Am. 2010 Mar;127(3):1528-36. doi: 10.1121/1.3299201.

Abstract

Biomechanical modeling and bifurcation theory are applied to study phonation onset and register transition. A four-mass body-cover model with a smooth geometry is introduced to reproduce characteristic features of chest and falsetto registers. Sub- and supraglottal resonances are modeled using a wave-reflection model. Simulations for increasing and decreasing subglottal pressure reveal that the phonation onset exhibits amplitude jumps and hysteresis referring to a subcritical Hopf bifurcation. The onset pressure is reduced due to vocal tract resonances. Hysteresis is observed also for the voice breaks at the chest-falsetto transition. Varying the length of the subglottal resonator has only minor effects on this register transition. Contrarily, supraglottal resonances have a strong effect on the pitch, at which the chest-falsetto transition is found. Experiment of glissando singing shows that the supraglottis has indeed an influence on the register transition.

MeSH terms

  • Biomechanical Phenomena / physiology*
  • Humans
  • Models, Biological*
  • Music
  • Nonlinear Dynamics
  • Phonation / physiology*
  • Thorax / physiology
  • Vocal Cords / physiology*
  • Voice / physiology*