Distortion-product otoacoustic emission (DPOAE) suppression data as a function of suppressor level (L 3) for f 2 frequencies from 0.5 to 8 kHz and L 2 levels from 10 to 60 dB sensation level were used to construct suppression tuning curves (STCs). DPOAE levels in the presence of suppressors were converted into decrement versus L 3 functions, and the L 3 levels resulting in 3 dB decrements were derived by transformed linear regression. These L 3 levels were plotted as a function of f 3 to construct STCs. When f 3 is represented on an octave scale, STCs were similar in shape across f 2 frequency. These STCs were analyzed to provide estimates of gain (tip-to-tail difference) and tuning (Q ERB). Both gain and tuning decreased as L 2 increased, regardless of f 2, but the trend with f 2 was not monotonic. A roughly linear relation was observed between gain and tuning at each frequency, such that gain increased by 4-16 dB (mean ≈ 5 dB) for every unit increase in Q ERB, although the pattern varied with frequency. These findings suggest consistent nonlinear processing across a wide frequency range in humans, although the nonlinear operation range is frequency dependent.
ASJC Scopus subject areas
- Arts and Humanities (miscellaneous)
- Acoustics and Ultrasonics