Two sources of acoustic distortion products from the human cochlea.

The amplitude and phase of both stimulus-frequency and distortion-product emissions have been measured in healthy human ears. In some ears it is possible to model acoustic distortion products (DPs) generated by low-to-moderate stimulus levels as the vector sum of two components originating from distinct regions of the cochlea, one from the f2 place and the other, with a longer delay, from the distortion product place. The phase lag of the more delayed DP component is slightly greater than that of stimulus frequency emissions (SFEs) measured in the same ears.