The suggests that the entire basilar membrane acts as a microphone, vibrating as a whole in response to a sound

Frequency theory of hearing

According to the frequency theory of hearing the auditory nerve's impulse corresponds to the frequency of a tone. This allows the recognition of pitch. Sounds are detected in the ear as acoustic signal in the external and middler ear. It is later on transformed in an electrical impulse that a nerve can detect in the cochlea. The theory assumes that a nerve can fire at rates of 20 to 20000 times per second. This is the assumption that the frequency of human hearing range is at 20 to 20000.