SOUND QUALITY EVALUATION OF ANTI-SATURATION CIRCUITRY IN A HEARING-AID

Loud sounds amplified by conventional hearing aids produce saturation distortion. This paper presents a comparison between a Class D hearing aid that was allowed to amplify into saturation and a Class D hearing aid that contained circuitry to prevent saturation distortion. The st udy was performed to determine whether users judged the conventional h earing aid or the anti-saturation hearing aid to have better sound qua lity. Seventeen subjects with hearing losses performed sound quality j udgments at two sites. At low input levels, where the measured distort ion was low, the subjects rated both hearing aids equal in sound quali ty. At high input levels, the subjects preferred the anti-saturation h earing aid, which had significantly lower distortion than the standard hearing aid. Though these data do not correlate the measured distorti on to the subjective sound quality, the relationship revealed between the two in this testing warrants further investigation.