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The Measurement of Unsteady Surface Pressure Using a Remote Microphone Probe
Published on: December 3, 2016
Probe-microphone measurements with body-worn instruments: loudspeaker and reference microphone effects
1Wendell Johnson Speech and Hearing Center, University of Iowa, Iowa City 52242-1012.
Journal of the American Academy of Audiology
|March 1, 1994
Summary
This study found that measurement locations significantly impact hearing aid performance results. For body-worn hearing aids, using the modified pressure method with a head-level loudspeaker and over-the-ear microphone best approximates standard behind-the-ear hearing aid measurements.
Area of Science:
- Audiology
- Hearing Aid Technology
- Acoustics
Background:
- Traditional probe-microphone measurements for behind-the-ear (BTE) and in-the-ear (ITE) hearing aids use standardized loudspeaker and microphone placements.
- These standard conditions may not accurately represent the in situ performance of body-worn hearing aids.
- Accurate in situ measurements are crucial for effective hearing aid fitting and performance verification.
Purpose of the Study:
- To compare the real-ear aided response (REAR) and real-ear insertion response (REIR) of a body-worn hearing aid under various measurement conditions.
- To evaluate the influence of loudspeaker and reference microphone positions on measurement outcomes.
- To determine the optimal measurement configuration for body-worn hearing aids that best correlates with standard measurement methods.
Main Methods:
- The study utilized the substitution method and an offline equalization modified pressure method.
- Measurements were taken with three loudspeaker locations (0° and 45° at head level, 0° at body level) and two reference microphone positions (over-the-ear [OTE] and next to the body aid).
- Real-ear aided response (REAR) and real-ear insertion response (REIR) were analyzed for each condition.
Main Results:
- Measurement outcomes for both REAR and REIR were significantly affected by changes in loudspeaker and reference microphone positions.
- The modified pressure method, with a 0° head-level loudspeaker and OTE reference microphone, showed the closest agreement to the standard substitution method (0° head-level loudspeaker).
- Correction values are necessary for REAR measurements when using the modified pressure method to approximate substitution method results, but not for REIR.
Conclusions:
- Loudspeaker and reference microphone placement critically influence hearing aid measurement results, particularly for body-worn devices.
- The modified pressure method with specific head-level loudspeaker and OTE microphone positions offers a more realistic assessment for body-worn hearing aids compared to other tested configurations.
- Clinicians should consider these findings and apply necessary corrections for accurate REAR measurements when fitting body-worn hearing aids.
