FIG. 1.

Frequency-specific stimulus level pairs accounting for compressibility of the basilar-membrane response at the f₂-tonotopic place, optimized to facilitate DPOAE acquisition with maximum amplitude of the nonlinear-distortion component. Dashed lines show the optimal stimulus levels of the f₁ tones, L₁, as a function of the stimulus levels of the f₂ tones, L₂, provided by the empirical relation in Zelle et al. [2015a; their Eq. (5)] which was derived experimentally from normal-hearing adult subjects. Symbols are stimulus-level pairs used here; they derive from preliminary results of that study. The frequencies f₂ were chosen to correspond to frequencies commonly used in clinical routine.