Experimental observations on the influence of supraglottal flow structures on phonation.
Zhaoyan Zhang, Juergen Neubauer · The Journal of the Acoustical Society of America · 2009
The supraglottal flow has been shown to exhibit many complex phenomena such as vortex shedding, jet oscillation, and recirculation. However, the influence of such airflow features on phonation is still unknown. The objective of this study is to evaluate the influence of the supraglottal flow structures on phonation characteristics. In a mechanical model of phonation, the interaction of the supraglottal flow with vocal folds was studied by using vocal tract tubes of different lengths mounted at different off-center positions and by disturbing the flow with cylinders of different diameters. Preliminary results show that, at normal phonation conditions, changes in the supraglottal flow structures did not lead to noticeable changes in phonation threshold and sound quality. However, for vocal fold models simulating pathological conditions, disturbing the supraglottal flow led to significant changes in phonation frequency, amplitude, and perceived sound quality. Possible mechanisms that could explain the observed difference will be discussed. [Work supported by NIH R01 DC009229.]