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An Automated System for Sound Localization Testing in Hearing-Impaired Listeners
Published on: March 13, 2026
The effect of frequency-dependent microphone directionality on horizontal localization performance in hearing-aid
Gitte Keidser1, Anna O'Brien, Jens-Uwe Hain
1National Acoustic Laboratories, Chatswood, Australia. gitte.keidser@nal.gov.au
International Journal of Audiology
|December 3, 2009
Summary
Frequency-dependent microphone directionality in hearing aids can improve sound localization, especially for distinguishing front from back sounds. This technology offers enhanced spatial awareness for hearing-impaired individuals.
Area of Science:
- Audiology
- Acoustics
- Hearing Science
Background:
- Sound localization relies on spectral cues, which are altered by microphone directionality.
- Hearing aid microphone directionality (omnidirectional, partial, full) affects spectral shape based on sound arrival direction.
- Hearing-impaired listeners often struggle with accurate sound localization, particularly front/back discrimination.
Purpose of the Study:
- To investigate how frequency-dependent microphone directionality influences horizontal-plane sound localization in hearing-impaired listeners.
- To compare localization performance with no hearing aid, omnidirectional, partial directionality, and full directionality settings.
- To evaluate the real-world effectiveness of different directionality settings.
Main Methods:
- Utilized a 360-degree loudspeaker array and five distinct spectral stimuli.
- Measured localization performance in 21 hearing-impaired listeners under various hearing aid conditions.
- Conducted field tests to assess performance in everyday listening environments.
Main Results:
- Localization accuracy was significantly poorer than normative data without hearing aids, with prominent front/back reversals due to high-frequency inaudibility.
- Front/back reversals persisted with omnidirectional microphones.
- Partial and full directionality showed improvements in front/back localization for stimuli with adequate mid- and high-frequency content, while left/right localization was negatively impacted by full directionality.
- Field tests showed no significant effects.
Conclusions:
- Frequency-dependent directionality provides alternative spectral cues that enhance front/back sound localization for hearing-aid users.
- Partial directionality appears beneficial for front/back localization without significantly impairing left/right localization.
- Further research may be needed to optimize directionality settings for comprehensive spatial hearing improvement.
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