Nonlinear Waves in the Ear and Sound Signal Processing
Jack Xin, Ph.D., Professor of Mathematics and ICES (Institute for Computational Engineering 
and Sciences), University of Texas, Austin

 
Abstract:
We present a class of dispersive nonlinear nonlocal partial differential 
equations (PDEs) modeling mechanics and neural functions of the inner ear,
 then discuss analytical and numerical properties of wave like solutions 
under single and multiple frequency sound inputs. The solutions reveal 
two tone and three tone suppression effects in qualitative agreement with
 cat auditory neural data. An associated nonlinear phenomenon at the 
perception level is masking, namely, an audible sound becomes inaudible in
 the presence of another sound. We introduce a PDE based two level 
psychoacoustic model on tonal masking of banded noise, and relate it to
 perceptual coding in digital music (MP3).