Figure 1. DPOAE growth functions from a gerbil ear (f2 = 10 kHz; f2/f1 = 1.20), against the intensity of equilevel primaries. Continuous lines, closed symbols: before sound exposure; dashed lines, open symbols: after exposure to a 6-kHz pure tone. The circles and squares correspond to two different ears. The thinner straight line marks a slope of 1 dB / dB increase of the primaries. Dotted line: average noise floor.