Laryngeal Activity and the Analysis and Synthesis of Speech
PHILIP H. LIEBERMAN · The Journal of the Acoustical Society of America · 1963
The activity of the larynx is a function of the tensions of the laryngeal muscular system, the mass of those parts of the vocal cords that are in motion, the losses caused by the collision of the vocal cord's margins, and the aerodynamic forces that act upon the vocal cords. The larynx is coupled through these aerodynamic forces to the rest of the respiratory system. The subglottal air pressure is affected by the resonances of the lungs and trachea. When the fundamental frequency of the glottal waveform or the lower harmonics of the fundamental frequency excite these resonances, the peak subglottal air pressure builds up. The superglottal air pressure is a function of the air flow through the vocal tract. Pressure transients result when constrictions occur during voicing. Variations in the glottal waveform, therefore, result from period to period, which causes rapid variations in the glottal source's spectrum and periodicity. This paper discusses the results of analyses of the acoustic waveform and high-speed ,notion pictures of the larynx and the relevence of these experimental results to the preservation of natural quality in speech synthesis.