COMODULATION MASKING RELEASE OVER A 3 OCTAVE RANGE

Comodulation masking release (CMR) for a variable frequency 50-ms tone-burst signal was measured in the usual manner, except that the overall level of the 100-Hz-wide masker band was varied from 18 to 78 dB SPL in 20-dB steps. The 100-Hz-wide cue band, which remained centered at 1000 Hz, was presented at an overall level of 78 dB SPL. Presentation was either monotic or dichotic, with the cue band presented to the nonsignal ear only. Averaged results show monotic CMR values as high as 7 dB when the masker band/signal was centered at 8000 Hz, or 3 oct away from the cue band, and 11 dB when it was 2 oct away. CMR for all frequency separations was reduced when the two noise bands were equal in level. The dichotic presentation resulted in a CMR that was somewhat smaller, and less dependent on, the relative levels of the two noise bands.