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Self-excitation Analyses Of Vocal Chord Under Breathing Flow And Frequency Change By Muscle Activation


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T. Tsuta, T. Iwamoto, T. Shimizu & D. Egusa


This paper presents some analyses and experiments on vocalizing mechanics in the vocal chord due to the breathing flow, and their wide range of frequency change by varying the interior muscle activations. Three-dimensional dynamic responses of the hyperelastic and finite deformation body of the vocal chord and the interior muscles have been analysed at first and the exclusive FEM system has been developed. The eigen frequencies and vibration characteristics of the vocal chord are analysed by varying the activation level of the interior muscles. The Helmholtz equation of the breathing flow under transient state has been analysed to obtain the pressure pulsation characteristics behind the vocal chord during vocalizing of the source voice. Combining both approaches stated above, the mechanism of the self-exciting vibration of the vocal chord has been studied in detail using the route-locus approach. It is also found in the analysis and experiments that the frequency of the selfexciting vibration can be widely varied with the activation level of the interior muscle of the vocal chord, giving rise to a variety of frequency levels of the source voice. 1 Introduction It is important to clarify theoretically the human’s vocalizing mechanics in the larynx-vocal tract system, in order to develop the artificial system for a