Abstract
Human voices originate from the vibration of vocal folds in the larynx. In most previous studies on voice generation, a planar sound source was assumed for a laryngeal sound source. However, no direct in vivo measurement of human sound pressure in the larynx has been reported. Therefore, detailed study of this sound pressure is necessary to elucidate mechanisms of human phonation. In the present study, the sound pressure in the larynx was experimentally analyzed to clarify the phonation mechanism and seek better modeling of vocal folds. This experiment focused on direct measurement of the sound pressure by means of a probe microphone and simultaneous observation of vocal fold movement by means of a high-speed digital camera. Experimental results show that the sound pressure measured above the glottis and in the inferior pharynx has the same frequency characteristics, although airflow velocity above the glottis and in the inferior pharynx has the quite different frequency characteristics. This is important because it provides crucial information to create better simulation models of the phonation mechanism.
