Hearing thresholds at high frequencies: Results obtained using a new measurement technique

The hearing thresholds for 40 young adults (18–26 years) were measured at 13 frequencies (8, 9,…,20 kHz) using a newly developed high‐frequency audiometer. All subjects were screened at 15‐dB hearing level at the low audiometric frequencies, had tympanometry within normal limits, and had no history of significant hearing problems. The audiometer delivered sound to the ear canal through a tube and earpiece in which a small calibrated microphone was located. For each ear, a calibration function relating sound pressure at the inner end of the ear canal to voltage at the acoustic source was calculated from an impulse recorded at the microphone. Calibration functions for different ears extended over a range of 15 dB at some frequencies. For some subjects cross modes in the ear canal prevented accurate calibration at the highest frequencies. Most high‐frequency audiograms exhibited a sharply sloping increase in threshold. The location in frequency of this abrupt increase in threshold differed considerably among...