Distortion product otoacoustic emissions generated by mistuned harmonic stimuli

Psychoacoustic research in humans [Lee and Green, J. Acoust. Soc. Am. 95, 718–725 (1994)] suggests that the detection of the mistuning of an harmonic when the harmonic complex and a mistuned component were presented simultaneously to the same ear stems, at least in part, from the resulting envelope interactions on the basilar membrane. Neurophysiological research in chinchillas [Sinex et al., Hear. Res. 168, 150–162 (2002)], provides evidence that such envelope interactions can be detected at the level of the inferior colliculus. The potential role of cochlear nonlinearites in determining the nature of the signal on the basilar membrane is explored by evaluating the DPOAE generated by multicomponent harmonic and inharmonic complexes. When harmonic complexes are used, the DPOAE all fall at harmonic frequencies. When inharmonic complexes are used, many nonharmonic DPOAE are detected.