Performance of assistive listening devices using insertion gain measures.

Abstract

The electroacoustic performance characteristics of seven assistive listening devices (ALDs), that did not need to be coupled with a hearing aid, were measured using real ear insertion gain. The ALDs, which included TV listening systems and personal amplification systems, were measured on ten subjects. Electroacoustic performance of the ALDs varied although there were similarities for different types of devices. Frequency responses were either basically flat or had an emphasis in the low or mid-frequency region. The majority of devices provided negligible amplification when set at or below half volume. Total harmonic distortion was 10% or less for most ALDs. Overall, insertion gain measures were found to be of value in evaluating the effectiveness of this type of amplification device.