Place theory

Place theory is a theory of hearing which states that our perception of sound depends on where each component frequency produces vibrations along the basilar membrane. Therefore, the pitch of a pure tone would be determined by where the membrane vibrates. In technical terms, it states that frequency is encoded according to the tonotopic organization of the neurons. It was first discovered by Helmholtz. Place theory competes with the rate theory of hearing, which instead states that pitch is signaled by the rate at which the neurons fire.

Pitch sharpening
The relative shortness of the basilar membrane contrasts with the large number of pitches which people can distinguish. Place theory is generally seen as incomplete, lacking a mechanism which would explain our large pitch resolution. Research using modern cochlear implants suggests that the perception of pitch may depend on both the neurons' location and rate at which they fire.