Understanding the multi-mass model and sound generation of vocal fold oscillation

When a speaker speaks, the vocal fold oscillates, generating a voice. The voice resonating in the vocal tract and in the mouth is converted to speech when the speaker changes the shapes of the mouth and tongue. When the vocal fold oscillates, a voice is generated because the vocal fold oscillation vibrates the air in succession, and the vocal fold oscillation triggers the generation of the fundamental frequency of the vocal fold as well as that of the harmonic sound at the same time. It is not easy to understand these sound generation principles acoustically, however, unless one is equipped with deep knowledge in the fields of physics and acoustics. In this paper, therefore, the vocal fold will be simplified as a multi-mass model, and a way to easily understand the principle that the fundamental frequency and harmonic sound are generated simultaneously by vocal fold oscillation will be presented.