The subjective evaluation of the expansion time constant in single-channel wide dynamic range compression hearing instruments.

The present study investigated the subjective evaluation of expansion time constants in single-channel wide dynamic range compression (WDRC) hearing instruments. Thirty participants utilized binaural WDRC hearing instruments for a two-week trial. Subjective evaluations were conducted by having each participant rate their satisfaction with the expansion time constant on a daily basis and by having each participant indicate their preferred expansion time constant following the completion of the two-week trial. Each change in expansion time constant significantly affected listener satisfaction; however, all time constants resulted in satisfactory performance. Of the users expressing a preference, 75% preferred fast-acting over slow-acting expansion. These findings suggest that dynamic expansion parameters play an important role in determining the effectiveness of the feature for a given listener.