Acoustic measures of low-frequency noise in extended high-frequency audiometry

Abstract

A very high signal-to-noise ratio is required for equipment designed for extended high-frequency audiometry because listeners with almost no hearing ability in the extended high-frequency range may have normal hearing sensitivity in the lower frequencies. Two commercially available systems designed for pure-tone audiometry were evaluated both in the conventional and extended high-frequency range. Unwanted lower frequency signals greater than the noise floor occurred predominantly at presentation levels of approximately 110 dB SPL or higher. Test tones in the extended high-frequency range should be restricted to levels that are not associated with lower frequency noise.