Distortion product otoacoustic emissions generated by mistuned harmonic stimuli

Psychoacoustic research in humans (Lee and Green, J. Acoust. Soc. of Am. 95, 718-725, 1994) suggests that the detection of mistuning of harmonics stem, at least in part, from the resulting amplitude modulation on the basilar membrane. Neurophysiological research in chinchillas (Sinex et al. Hear. Res. 168, 150-162, 2002), provides evidence that such envelope modulations can be detected at the level of the inferior colliculus. The potential role of cochlear nonlinearities in determining the nature of the signal on the basilar membrane is explored by evaluating the DPOAE generated by multicomponent harmonic and inharmonic stimuli. When harmonic stimuli are used the DPOAE all fall at harmonic frequencies. When the stimuli are inharmonic many nonharmonic DPOAE are detected.