Cochlea & Hearing (2D) — Unrolled Basilar Membrane

Greenwood tonotopic map · travelling-wave envelope

Input

Frequency: 1000 Hz

Second tone

Second tone: 2000 Hz

Animate travelling wave

Hearing-loss region (~4 kHz)

Presets

Live readout

Input frequency—

BM position—

Tonotopic label—

Excited region—

Unrolled basilar membrane, base (stiff, high pitch) on the left, apex (floppy, low pitch) on the right. Position follows the Greenwood function f = A(10^ax − k). The travelling wave grows toward the characteristic place then is sharply cut off past it — this is why pitch is coded by place on the membrane.