Basal cochlear gain control is fast but limited to about 1 kHz bandwidth.

Evidence

The mechanical nonlinearity of the mammalian cochlea is clearly fast, but not instantaneous. The results of the current investigation show that dynamic changes in stimulus intensity can only be followed accurately up to a rate of ~ 1 kHz in the basal turn of the gerbil cochlea. This limitation appears to be produced by a low-pass gain control filter of some kind: this could be a mechanical filter, imparted by the load on a force generating element (such as a motile outer hair cell, or OHC), or an electrical filter (such as the OHC’s basolateral membrane, cf. Housley and Ashmore 1992 ). — Dijk, Pim van, Physiology, Psychoacoustics and…, 3628