Reverberation strength perceived by normal-hearing listeners predictable based on time-varying binaural loudness.

Previous work has explored novel binaural combinations of reverberation and the resulting perceived reverberation strength (reverberance). The present study examines the perceptual effects of additional binaural combinations of reverberation with the goal of explaining reverberance in terms of basic psychoacoustic principles. Stimuli were generated using virtual space techniques simulating a speech source 3 m to the listener's right in a moderately reverberant environment. Reverberant energy at the ears was varied systematically relative to the natural level for the environment (0-dB gain). The method of magnitude estimation was used to estimate reverberance. Four experiments were conducted. Experiment 1 tested monaural listening conditions for both left and right ears at reverberation gains from -21 dB to 0 dB. Experiment 2 tested a binaural listening condition where only reverberant energy at the ear farther from the source was manipulated (-21 dB to 0 dB). Experiment 3 tested two binaural conditions over a wider range of reverberation gains (-18 dB to +24 dB). In one condition, reverberant energy was manipulated for both ears equally. In the other condition, reverberant energy was manipulated only for the ear nearer the source. In Experiment 4, reverberant tails of the stimuli were removed to test whether listeners were able to use ongoing reverberant information to judge reverberance. The results from all experiments were found to be well predicted by a model of time-varying binaural loudness that focused on "glimpses" in time with relatively high reverberant sound energy and low direct sound energy. These findings suggest that the mechanisms underlying reverberance and loudness may be similar.