“…Interference causes the fine structure in plots of DPOAE amplitude versus f 2 (Heitmann et al, 1998;Mauermann et al, 1999;Talmadge et al, 1999); that is, these so-called DP-grams contain amplitude maxima and minima at stimulus frequencies of constructive and destructive interference, respectively (Kemp and Brown, 1983;Gaskill and Brown, 1990). The pattern of the DPOAE fine structure was reported to shift along the f 2 -axis with changing primary-tone levels (He and Schmiedt, 1993;Whitehead et al, 1995a), inducing large deviations in the shape and slope of I/O-functions in L 1 ,L 2 space, as also reported later by others (Mauermann and Kollmeier, 2004;Dalhoff et al, 2013). In other words, previously reported primary-tone levels for maximum DPOAE amplitude may have been biased due to wave interference between the two DPOAE components.…”