Nonlinearity of the Middle Ear as a Possible Source of Subharmonics

The asymmetric restoring force of the middle‐ear structure is considered as a possible source of subharmonics in the hearing system. A theoretical estimate of the required intensity of acoustical excitation to generate the subharmonic can be calculated in terms of the parameters describing the mechanical characteristics of the middle ear. It is found that, for damping characterized by a decay modulus of about 50 msec, the minimum sound‐pressure level must be greater than 122 dB in order to produce a subharmonic having a frequency one‐half that of the stimulating signal.