In Brief:
The gain of wide dynamic range compression hearing aids can be significantly different depending on whether a speech or non-speech input signal is used. The purpose of this study was to explore the reason(s) for this gain difference. A master, programmable digital hearing aid was used, and the effects of release time, compression ratio, and number of compression channels on the difference in gain (in 1/3 octave bands) between speech and non-speech input signals were evaluated. For most non-speech signals at most frequencies, the compression parameters accounted for more than 70% of the variance in gain differences, with release time and compression ratio having the greatest effects. Compression signal processing is therefore a primary cause of differences in hearing aid gain between speech and non-speech signals. It is recommended that hearing aid gain be measured with a real speech signal or a non-speech signal that has spectral and temporal properties similar to speech.
