Toward a Real-World Technical Test Battery for Remote Microphone Systems Used with Hearing Prostheses

Area of Science:

• Audiology
• Acoustics
• Signal Processing

Background:

• Remote microphones (RMs) enhance speech reception beyond unaided listening.
• Current RM assessment standards use unrealistic anechoic conditions.
• Real-world RM performance, especially in reverberant spaces, is under-investigated.

Purpose of the Study:

• To evaluate the electroacoustic performance of five RMs in a low-reverberation environment.
• To pilot physical and electroacoustic measures for RM characterization in diffuse-field conditions.
• To assess RM performance using computer models for speech intelligibility and quality.

Main Methods:

• Compared electroacoustic performance of five RMs in a low-reverberation room.
• Adapted IEC 60118 standards for diffuse-field testing and adaptive signal processing.
• Utilized computer models to predict speech intelligibility and quality with background noise.

Main Results:

• Five RMs showed similar predicted speech intelligibility across two noise levels.
• Adaptive signal processing in some RMs rendered noise bands irrelevant.
• Significant differences in transmission delay (40-50 ms) were noted in two RMs, nearing acceptability limits.

Conclusions:

• RM performance in realistic acoustic conditions is crucial for effective use.
• Adaptive signal processing needs careful consideration to avoid over-processing speech signals.
• Transmission delay is a key differentiator in RM performance, impacting audio-visual synchrony.