Aeroacoustic source characterization in a physical model of phonation

Area of Science:

• Acoustics
• Biophysics
• Speech Science

Background:

• Phonation, the production of sound by the vocal folds, is a complex biomechanical process.
• Understanding the relationship between vocal fold dynamics and sound output is crucial for diagnosing and treating voice disorders.

Purpose of the Study:

• To benchmark a physical model of the adult human airway against existing excised larynx models.
• To empirically demonstrate the link between vocal fold drag and sound production.

Main Methods:

• Measurements were taken using a physical model of the adult human airway.
• The model's performance was benchmarked against published data from excised larynx models.
• Concurrent measurements of vocal fold behavior (using transglottal pressure as a surrogate for drag) and radiated sound were analyzed.

Main Results:

• The physical airway model exhibited higher glottal volume flow, lower glottal resistance, and less fundamental frequency variation compared to excised larynx models.
• A strong correlation was observed between unsteady transglottal pressure (vocal fold drag) and radiated sound measured at the mouth.
• Specific acoustic features, like the ratio of the first and second harmonics, showed significant correlation between transglottal and mouth pressures.

Conclusions:

• Vocal fold drag is empirically demonstrated as the principal source of sound in human phonation.
• The physical airway model provides a reliable platform for studying phonation dynamics.
• These findings have implications for understanding voice production and developing therapeutic strategies.