Influence of Voice Focus on Auditory Feedback Control of Speech Using Long-Term Average Spectrum, Phon Spectrum, and...

Area of Science:

• Speech Science
• Acoustic Phonetics
• Voice Production

Background:

• Auditory feedback is crucial for speech motor control.
• Oronasal balance affects voice quality and perception.
• Voice focus strategies can alter speech production parameters.

Purpose of the Study:

• To investigate how voice-focus adjustments influence oronasal balance.
• To examine the effect of voice focus on auditory feedback control of speech.
• To analyze spectral distribution, perceived loudness, and nasal vibrations during different voice focuses.

Main Methods:

• Speech-language pathologists produced sustained vowels and read passages with forward, backward, and natural voice focuses.
• Low-frequency power (LFP) of vocal fundamental frequency was analyzed for audio-vocal feedback.
• Nasal accelerations and long-term average spectra (converted to phon spectra) were measured.

Main Results:

• Forward voice focus increased nasal acceleration and reduced LFP, indicating improved audio-vocal feedback control.
• Voice focus adjustments correlated with average power and phon values in the 0.2- to 0.3-kHz band.
• In noise, perceived loudness in the 0.5- to 2.3-kHz band predicted LFP better than average spectral power.

Conclusions:

• Voice-focus adjustments significantly alter vocal tract acoustics and audio-vocal integration.
• The impact of voice focus is pronounced when sound intensity or perceived loudness changes within the 0.2- to 2.3-kHz range.
• Forward voice focus may enhance speech control through increased oronasal coupling.