A nonlinear, nonlocal cochlear model of the transmission line type is
studied in order to capture the multitone interactions and resulting
tonal suppression effects. The model can serve as a module for voice
signal processing, and is a one-dimensional (in space) damped dispersive
nonlinear PDE based on the mechanics and phenomenology of hearing. It
describes the motion of the basilar membrane (BM0 in the cochlea driven
by input pressure waves. Both elastic dampling and selective longitudinal
fluid damping are present. The forner is nonlinear and nonlocal in BM
displacement, and plays a kep role in capturing tonal interactions. The
latter is active only near the exit boundary (helicotrema), and is built
in to damp out the remaining long waves. The initial boundary value
problem is numerically solved with a semi-implicit second order finite
difference method. Solutions reach a multi-frequency quai-steady state.
Numerical results are shown on two tone suppression. Suppression effects
among three tones are demonstrated by showing how the response magnitudes
of the fixed two tones are reduced as we vary the third tone in frequency
and amplitude. We observe qualitative agreement of our model solutions
with exisiting cat auditory neural data. The model is thus a simple and
efficient processing tool for voice signals.