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Fig. 8. Intensity of spectrum peaks of a 16 kHz tone (solid line, diamonds) at 1125
Hz at various pressure levels (SPL). Each point (diamond) represents an
average of 1000 stimulus presentations. The linear regression of the spectrum
peaks (broken line, open circles) is based on points from 70–110 dB. The
threshold for the tone is defined as the point where the regression line
crosses zero on the response scale, in this case 69.8 dB.