The acoustic coupling between the voice production system and the vocal tract has a significant influence on the production of voice. In this study, the coupling effect was represented using the acoustic pressure difference across the glottis, which is capable of inducing a flow, and the mean acoustic pressure in the glottis, which acts as a driving force for the vocal folds. These specific acoustic pressures were then interpreted in the frequency domain in the form of frequency responses, and incorporated into a model of the voice production system. In this framework, we were able to test the effect of source-filter coupling by filtering frequency responses. Numerical results revealed that these responses and the input impedance of the vocal tract both exhibited a dominant peak around 4 kHz. In addition, voice production simulations revealed that this high-frequency peak has a significant influence on the spatio-temporal pattern of glottal volume flow and vocal fold movements.
Bibliographic reference. Kaburagi, Tokihiko (2011): "Frequency-domain representation of source-filter coupling and its effect in the production of voice", In INTERSPEECH-2011, 2689-2692.