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Article
Specification of Absorbed-sound Power in the Ear Canal: Application to Suppression of Stimulus Frequency Otoacoustic Emissions
The Journal of the Acoustical Society of America (2011)
  • Kim Schairer, University of Wisconsin
  • Douglas H. Keefe, Boys Town National Research Hospital
Abstract
An insert ear-canal probe including sound source and microphone can deliver a calibrated sound power level to the ear. The aural power absorbed is proportional to the product of mean-squared forward pressure, ear-canal area, and absorbance, in which the sound field is represented using forward (reverse) waves traveling toward (away from) the eardrum. Forward pressure is composed of incident pressure and its multiple internal reflections between eardrum and probe. Based on a database of measurements in normal-hearing adults from 0.22 to 8 kHz, the transfer-function level of forward relative to incident pressure is boosted below 0.7 kHz and within 4 dB above. The level of forward relative to total pressure is maximal close to 4 kHz with wide variability across ears. A spectrally flat incident-pressure level across frequency produces a nearly flat absorbed power level, in contrast to 19 dB changes in pressure level. Calibrating an ear-canal sound source based on absorbed power may be useful in audiological and research applications. Specifying the tip-to-tail level difference of the suppression tuning curve of stimulus frequency otoacoustic emissions in terms of absorbed power reveals increased cochlear gain at 8 kHz relative to the level difference measured using total pressure.
Keywords
  • sound pressure,
  • acoustical measurements,
  • calibration,
  • middle ear mechanics,
  • otoacoustic emission
Publication Date
2011
DOI
10.1121/1.3531796
Publisher Statement
Copyright 2011 Acoustical Society of America. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the Acoustical Society of America.

The following article appeared in Douglas H. Keefe, and Kim S. Schairer, Specification of absorbed-sound power in the ear canal: Application to suppression of stimulus frequency otoacoustic emissions, The Journal of the Acoustical Society of America 129, 779 (2011) and may be found at https://doi.org/10.1121/1.3531796.
Citation Information
Kim Schairer and Douglas H. Keefe. "Specification of Absorbed-sound Power in the Ear Canal: Application to Suppression of Stimulus Frequency Otoacoustic Emissions" The Journal of the Acoustical Society of America Vol. 129 Iss. 2 (2011) p. 779 - 791 ISSN: 1520-9024
Available at: http://works.bepress.com/kim-schairer/7/