FIG. 9.
Dependence of thresholds referenced to Pfor when the surge impedance (Z0) is assumed fixed is reduced using a procedure that estimates Z0 from the ear-canal impedance. The absolute values of threshold changes (errors) in each subject for the two calculations were subtracted, recognizing that the sign of the error was less important than its magnitude. Improved performance is greatest near the frequencies of quarter-wave resonance (∼5 and 13 kHz). The thick line and error bars represent the mean (+/−1 SEM).