Acoustic distortion products in humans: Systematic changes in amplitude as a function of f2/f1 ratio

• DOI: 10.1121/1.397728
• Publication Date: 2005-10-13T18:57:10Z
• Authors: F. P. Harris; B. L. Lonsbury-Ma...; B. B. Stagner; A. C. Coats; G. K. Martin
• Keywords: Distortion (music); Tone (literature); Separation (statistics)

The effects of primary-tone separation on the amplitude distortion-product emissions (DPEs) at 2f1−f2 frequency were systematically examined in ten ears five subjects. All individuals had normal hearing and middle-ear function based upon standard clinical measures. Acoustic-distortion products elicited 1, 2.5, 4 kHz by equilevel primaries 65, 75, 85 dB SPL, while f2/f1 ratios varied 0.02 increments from 1.01–1.41 (4 kHz), 1.01–1.59 (2.5 or 1.01–1.79 (1 kHz). A principal outcome reflected detailed structure both average individual ratio functions was a nonmonotonic change DPE as increased. Despite presence nonmonotonicities, there clearly region f1 f2 that generated maximum DPE. amplitudes related to level. For all three levels stimulation, inversely frequency. Thus larger reflecting greater more effective generating DPEs 1 rather than kHz. optimal for 2.5 fell an intermediate value. Conversely, acoustic level directly primary tones. Regardless tones, smaller superior response 65-dB stimuli, whereas bigger with 75 SPL. Within any specific stimulus–parameter combination, variability noted. When stimulus conditions describing variations considered, 1.22 most maximizing amplitude.