The effect of audibility, signal-to-noise ratio, and temporal speech cues on the benefit from fast-acting compression in modulated noise.

The objective of the experiment was to investigate three aspects that might contribute to the benefit of fast-acting compression seen in normal-hearing listeners. Six normal-hearing listeners were tested with speech recognition in a fully modulated noise (FUM) either through a fast-acting compressor or through linear amplification. In the first experiment, three different presentation levels of the FUM noise (15, 30, and 45 dB SL) were tested. The second experiment manipulated the control signal of the compressor independently of the audio input signal at four signal-to-noise ratios (-15, 10, -5, and 0 dB). A signal correlated noise version of the speech signal was tested in the third experiment at three speech-to-noise ratios (-20, -15 and -10 dB). Results showed that performance was better with compression than with linear amplification through all of the tested conditions at least when the signal-to-noise ratio was negative. The results suggest that other aspects of the hearing impairment than those simulated here are involved in the degraded performance seen for some hearing-impaired listeners with fast-acting compression.