A. Michael Noll & others - Simulated Basilar Membrane Motion (1966)

Produced at Bell Labs in 1966 by Robert C. Lummis, A. Michael Noll and Man Mohan Sondhi.

"The basilar membrane is a pseudo-resonant structure that, like strings on an instrument, varies in width and stiffness. The "string" of the basilar membrane is not a set of parallel strings, as in a guitar, but a long structure that has different properties (width, stiffness, mass, damping, and the dimensions of the ducts that it couples to) at different points along its length. The motion of the basilar membrane is generally described as a traveling wave. The parameters of the membrane at a given point along its length determine its characteristic frequency (CF), the frequency at which it is most sensitive to sound vibrations. The Basilar membrane is widest (0.42–0.65 mm) and least taut at the apex of the cochlea, and narrowest (0.08–0.16 mm) and most taut at the base. High-frequency sounds localize near the base of the cochlea (near the round and oval windows), while low-frequency sounds localize near the apex." - Wikipedia.

This movie is to be viewed with eyes crossed to produce a 3-Dimensional visual effect.