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Publication Citation: Methods for hearing aid directivity index measurements under simulated real-ear conditions

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Author(s): Randall P. Wagner;
Title: Methods for hearing aid directivity index measurements under simulated real-ear conditions
Published: September 01, 2005
Abstract: One technique traditionally used to measure the directivity index of hearing aids involves acquiring data with sound source locations (at multiple azimuth angles) restricted to the horizontal plane. For measurement of the directivity index of a hearing aid under simulated realear conditions, this technique provides limited accuracy due to the inherent asymmetry of the directional response of a manikin-mounted aid. To address this limitation, Working Group 48 of the ANSI Standards Committee S3 on Bioacoustics worked on the development of standardized procedures with sound source locations out of the horizontal plane. One such procedure specifies sound source locations on the surface of an icosohedron. The revision of ANSI standard S3.35 eventually developed by this working group specifies forty-eight sound source locations on a spherical surface centered about the point on the manikin bisecting the line joining the centers of the ear canals. Details regarding the test setups and procedures used at the National Institute of Standards and Technology to support this development effort will be discussed. Data obtained with the different techniques will also be presented. [Work supported by the Department of Veterans Affairs.]
Conference: Journal of the Acoustical Society of America, Program: 150th Meeting of the Acoustical Society of America
Volume: 118
Issue: No. 3, Part 2
Location: Minneapolis, MN
Dates: October 17-21, 2005
Keywords: Directivity index;directivity index measurements;hearing aid measurements;hearing aids
Research Areas: Acoustical pressure measurement