A comparison of sound quality judgments for monaural and binaural hearing aid processed stimuli

Fifteen adults with bilaterally symmetrical sensorineural hearing loss of mild and/or moderate degree were given a paired-comparison task designed to elicit magnitude preference judgments for binaural/monaural hearing aid processed signals. Stimuli consisted of speech-in-quiet, speech-in-noise, and music, each of which were recorded in three listening environments (audiometric test booth, living room, and a music/lecture hall) through hearing aids placed on a Knowles Electronics Manikin for Acoustic Research (KEMAR). Caution was exercised throughout recording and playback procedures to ensure symmetry and accuracy of presentation levels through insert earphones. Stimuli were presented at most comfortable listening levels. Judgments were repeated three times for each of nine test conditions (three listening environments and three stimuli) on eight separate sound quality perceptual attributes (brightness, clarity, fullness, loudness, nearness, overall impression, smoothness, and spaciousness).;Subjects ranked each perceptual attribute with respect to its importance for binaural listening relative to monaural. Clarity was ranked the most important and brightness was the least important attribute. Of the five subjects who were non-hearing aid users, four expressed a monaural hearing aid preference prior to the study. After listening to the test tapes, these four subjects switched their preference to binaural hearing aids.;Utilization of a paired-comparison format to demonstrate binaural/monaural hearing aid sound quality differences to improve hearing aid informative counseling may be useful.;Results revealed binaural preferences for all eight perceptual attributes. There were no statistically significant effects for listening environment. The stimulus factor was significant only for fullness and spaciousness. For the latter attributes, binaural preferences were strongest for speech-in-quiet. Trial (test versus two retest trials) was statistically significant only for overall impression, smoothness, and spaciousness. Intertrial correlations revealed a possible learning effect with highest correlations between the second and third trials across perceptual attributes.