5aPP2. Cochlear nonlinearity: Implications for auditory signal processing and perception.

Session: Friday Morning, May 17

Time: 8:35

Author: Hendrikus Duifhuis
Location: Biophys. Dept. & BCN Grad. School for Behavioral and Cognit. Neurosci.), RUG, Nijenborgh 4, 9747 AG Groningen, The Netherlands


Conscious perception of auditory nonlinearity in combination tones, the low-frequency intermodulation products of two or more tones, goes at least back to Tartini (1692--1770). Renewed interest around 1970 [e.g., J. L. Goldstein, J. Acoust. Soc. Am. 41, 676--689 (1967); J. L. Hall, J. Acoust. Soc. Am. 56, 1818--1828 (1974); G. F. Smoorenburg, J. Acoust. Soc. Am. 52, 615--632 (1972)] led to the conclusion that the nonlinearity originates in the (intact) cochlea. At that time, nobody paid special attention to the point that acoustical effects within the cochlea should be reflected at the aural entrance. Today, that issue (DPOAE) is actively explored. The link with auditory perception receives lesser emphasis, hopefully not because a proper psychoacoustic measurement requires more than reading a stimulus parameter (cf. Psychoacoustics and David M. Green). Next, two-tone suppression became an issue where psychological and physiological nonlinear acoustics met. The phenomena are intertwined, and probably inseparable from the point of view of underlying biophysical mechanism. Finally, obviously the auditory nonlinearity is compressive. The negligible impact of this result on development of a biophysical basis for the auditory dynamic range and the decibel scale remains puzzling.

from ASA 131st Meeting, Indianapolis, May 1996