Cochlear compression makes response gain peak near the moment of maximal two-tone cancellation

Evidence

3.1 Time-Domain Observations BM responses to well balanced, “beating” two-tone stimuli had heavily compressed envelopes, as illustrated in Fig. 1 . The amount of compression was quantified by comparing the shapes of the observed response envelopes with those that would be predicted in a completely linear system (illustrated by the dashed blue and red lines in Figs. 1 b and c , respectively). When scaled to have similar peak magnitudes, the observed envelopes exceeded the linear predictions across most of the beat cycle (cf. Fig. 1 b , c ). Expressing the ratios of the observed and predicted envelopes as “normalised gains” (Fig. 1 d ), the envelope’s maximum gain always occurred near (but not exactly at) the instant of maximal cancellation between the two beating tones. This is as expected in a compressive system, where (by definition) “gain” decreases with increasing intensity, or increases with decreasing intensity. — Dijk, Pim van, Physiology, Psychoacoustics and…, 3637