Effects of modulation method and presentation part on distantly-presented bone-conducted ultrasonic perception

Area of Science:

• Acoustics
• Biomedical Engineering
• Human-Computer Interaction

Background:

• Bone-conducted ultrasound (BCU) transmits speech via amplitude-modulation and can be perceived distantly on the body.
• Distantly-presented BCU is a potential technology for selective audio devices where users touch a vibrator.

Purpose of the Study:

• To assess how stimulus placement affects the perception of distantly-presented BCU.
• To investigate the impact of amplitude-modulation methods on speech intelligibility using BCU.

Main Methods:

• Measured vibration acceleration in the external auditory meatus and hearing thresholds for distantly-presented BCU.
• Evaluated Japanese monosyllable articulation using different amplitude-modulation techniques (DSB-TC, Transposed, DSB-SC, SSB).

Main Results:

• Ultrasound attenuation increased with more complex presentation parts; factors beyond distance affected forearm BCU perception.
• Amplitude-modulation methods significantly impacted speech perception, with DSB-TC and Transposed yielding higher articulation scores.

Conclusions:

• Stimulus placement and modulation method are critical factors for effective distantly-presented BCU audio transmission.
• Findings offer valuable insights for developing novel audio devices utilizing distantly-presented BCU technology.