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

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.

Influence and interactions of laryngeal adductors and cricothyroid muscles on fundamental frequency and glottal posture control

“…Acoustically, these differences in harmonic strength were demonstrated by spectral analysis. When viewed by TA levels, distinct areas of large change in F0 value with incremental change in strain could be observed, consistent with the definition of F0 jumps between the chest-like and falsetto-like registers ( Svec et al, 1999;Tokuda et al, 2010). These two F0 clusters variably overlapped in terms of strain: at TA level 0, only two F0 data points were in the higher F0 cluster and there was no overlap in strain [ Fig.…”

Source-tract interaction with prescribed vocal fold motion

“…This is known as a level II model (Titze, 2008). The past few years has seen theoretical, numerical simulation, and experimental work in the area of level II sourcetract interaction (e.g., Svec et al, 2008;Titze, 2008;Titze et al, 2008;Titze and Morely Worely, 2009;Tokuda et al, 2007;Zañartu et al, 2011). These studies show that sourcetract interaction is an important factor when considering voice register changes in response to changes in laryngeal settings.…”

Analysing and Understanding the Singing Voice: Recent Progress and Open Questions

“…Based on such models, register transitions can be realised by simulating a muscle activity that corresponds to the transfer between two distinct sets of parameters [126]. f o gliding has been simulated by several models [88,113,127,128]. Moreover, hysteresis of transitions between chest and falsetto registers and voice instabilities observed during the register transitions in excised larynx experiments [129][130][131] have been also studied [113,128].…”

“…f o gliding has been simulated by several models [88,113,127,128]. Moreover, hysteresis of transitions between chest and falsetto registers and voice instabilities observed during the register transitions in excised larynx experiments [129][130][131] have been also studied [113,128]. The hysteresis implies coexistence of two registers within the same physiological condition of the vocal folds, which is essential for realising an abrupt transition between the registers.…”

“…The hysteresis implies coexistence of two registers within the same physiological condition of the vocal folds, which is essential for realising an abrupt transition between the registers. As one of few models that simulate the register transitions, a four-mass body-cover polygon model is considered here [128]. This model was developed to replicate as closely as possible the sudden chest-falsetto transitions and the accompanying phenomena observed in a singing Voice…”