A model for cochlear mechanics is proposed to take account of its two systems, one passive
and one active. The classical passive system stimulates the inner hair cells directly at levels
above about 40 dB SL. At intensities below about 60 dB an active process, the 'cochlear
amplifier'(CA), somehow provides additional energy that enhances the vibration of a narrow
segment of the basilar membrane near the apical foot of the familiar, traveling wave
envelope. The outer hair cells are essential for CA. The active system acts like a high-Q …