Computer model to characterize the air volume displaced by the vibrating vocal cords

Area of Science:

• Acoustics
• Speech Science
• Computational Phonetics

Background:

• Understanding vocal cord dynamics is crucial for speech production.
• Previous models have not fully quantified the acoustic impact of vocal cord displacement.
• The role of air volume displacement in glottal flow requires detailed investigation.

Purpose of the Study:

• To quantitatively assess the acoustic effects of air volume displaced by vibrating vocal cords.
• To determine the contribution of this displacement current to overall glottal volume velocity.
• To synthesize speech sounds with and without the displacement current to evaluate its perceptual significance.

Main Methods:

• Utilized a pre-existing vocal-cord/vocal-tract model.
• Performed computer simulations to analyze lateral and longitudinal vocal cord motion.
• Synthesized speech signals, comparing versions with and without the displacement current's influence.

Main Results:

• The displacement current was found to be a second-order effect compared to total glottal flow.
• This displacement contribution was identifiable in time waveforms and spectra of glottal and mouth velocities.
• Synthesized speech demonstrated that the displacement current's effect is subtle.

Conclusions:

• Vocal cord air volume displacement is a minor contributor to glottal flow and sound excitation.
• The displacement current's acoustic impact is discernible primarily through differential analysis.
• Further research can refine speech synthesis models by considering these subtle acoustic effects.