A quantitative model of voice F0 control

Area of Science:

• Biomechanics
• Laryngeal Physiology
• Acoustic Phonetics

Background:

• Understanding voice production requires modeling the complex biomechanics of the larynx.
• Previous models have simplified laryngeal muscle and cartilage interactions.

Purpose of the Study:

• To develop a biomechanically-based mathematical model of the larynx.
• To investigate the relationship between laryngeal muscle activity, subglottal pressure, and vocal fold vibration characteristics, particularly fundamental frequency (F0).

Main Methods:

• Constructed a mathematical model incorporating the cricoid and thyroid cartilages, thyroarytenoid (TA), cricothyroid pars rectus (CTr), and cricothyroid pars oblique (CTo) muscles, and associated ligaments.
• Calculated equilibrium positions and tensions for laryngeal components based on muscle activation and subglottal pressure (PS).
• Determined vocal fold tensions and lengths to predict fundamental frequency (F0) of vibration.

Main Results:

• Thyroarytenoid (TA) muscle activity shortened vocal folds, while increased cricothyroid (CTr, CTo) activity and PS lengthened them.
• Muscle activation increased vocal fold tension; PS had minimal effect.
• Fundamental frequency (F0) generally increased with CTr, CTo, and PS, but TA activity showed a non-monotonic effect.
• Optimal F0 control involved co-contraction at low frequencies, shifting to sustained CTr/CTo and decreasing TA activity for higher frequencies.

Conclusions:

• The model provides insights into normal and abnormal voice production mechanisms.
• Findings offer constraints for neural modeling of voice control.
• Laryngeal biomechanics significantly influence vocal fold dynamics and pitch regulation.