Abstract
Using the Mössbauer technique, we have studied the vibration of the human basilar membrane and malleus head in the sound frequency range 0.2-9.0 kHz and at a sound pressure of 100 dB at the tympanic membrane. The displacement frequency response curves for the basilar membrane and the malleus head have similar shapes, with a maximum at about 1 kHz. Below and above 1 kHz the curves have a slope of about 10 dB/octave and -100 dB/octave, respectively. In addition, the basilar membrane has a maximum displacement at a frequency-dependent distance from the stapes. A simple hydro-dynamic model for the cochlea is used to interpret the experimental data. A possible mechanism for the frequency resolution of sound by the ear and noise-induced hearing loss is discussed.