Effects of hand postures on voice directivity

Area of Science:

• Acoustics
• Speech Science
• Human-Computer Interaction

Background:

• Voice directivity, the directional properties of sound emission from the human voice, is crucial for speech intelligibility and communication.
• Previous research has primarily focused on phoneme-dependent variations in voice directivity, with less attention paid to articulatory gestures like hand postures.
• Understanding factors influencing voice directivity is essential for applications ranging from telecommunications to assistive technologies.

Purpose of the Study:

• To investigate and quantify the impact of specific hand postures on the spherical voice directivity of the vowel /a/.
• To compare the magnitude of directivity changes caused by hand postures with those caused by phoneme variations.

Main Methods:

• Spherical voice directivity datasets were collected from 13 subjects articulating the vowel /a/.
• Measurements were performed using a 32-microphone spherical microphone array.
• Data were subsequently upsampled to achieve a higher spatial resolution for detailed analysis.

Main Results:

• Hand postures were found to significantly alter voice directivity, demonstrating a substantial impact on the directivity index.
• The observed changes in directivity index due to hand postures reached up to 6 dB.
• This effect was found to be more pronounced than the variances typically attributed to phoneme-dependent differences.

Conclusions:

• Hand postures represent a significant, often overlooked, factor influencing human voice directivity.
• The magnitude of change in voice directivity induced by hand postures can exceed that of phoneme variations.
• These findings have implications for speech production models, acoustic simulations, and the design of voice-enabled technologies.