Vocal Tract Resonance Detection at Low Frequencies: Improving Physical and Transducer Configurations

Area of Science:

• Acoustics
• Speech Science
• Bioacoustics

Background:

• Non-invasive estimation of vocal tract resonances is crucial for speech and singing analysis.
• Current broadband excitation methods struggle with low-frequency resonances (<500 Hz) due to poor signal-to-noise ratios caused by lip radiation impedance.
• Limitations hinder accurate investigation of the first vocal tract resonance.

Purpose of the Study:

• To investigate physical configurations for optimizing acoustic coupling between transducers and the vocal tract.
• To identify a practical arrangement for enhanced sensitivity in detecting low-frequency vocal tract resonances.
• To develop quantitative analysis methods for comparing resonance detection sensitivity and quality.

Main Methods:

• Systematic investigation of various physical configurations for transducer placement.
• Development and application of two quantitative analysis methods for sensitivity and quality assessment.
• Experimental evaluation of acoustic coupling and low-frequency response in different setups.

Main Results:

• An optimal physical configuration was identified, demonstrating superior acoustic coupling and low-frequency response compared to existing methods.
• The optimal configuration reliably detects vocal tract resonances down to 350 Hz, and potentially lower.
• Improved signal-to-noise ratios at low frequencies were achieved, overcoming previous measurement limitations.

Conclusions:

• The identified optimal configuration significantly enhances the ability to measure low-frequency vocal tract resonances.
• This advancement allows for confident estimation of the first vocal tract resonance across a wide range of vowel articulations.
• The findings pave the way for more comprehensive non-invasive analysis of speech and singing production.