On the Generation of Odd-Fractional Subharmonics

In chinchilla ears, between 1000 and 3000 Hz, the common one-half-frequency subharmonic is not present. Instead, pairs of odd-fractional subharmonics are seen. These distortion components appear at threshold only in specific frequency relations with the fundamental. Above threshold, both the frequency and the magnitude of the subharmonic depend on the stimulus intensity. With direct mechanical stapes stimulation and with various probe-tone experiments, it was shown that the odd-fractional subharmonics originate in the inner ear. The phenomenon of subharmonic squelch effect was described.