title: Performance of a fully adaptive directional microphone to signals presented from various azimuths.
abstract: The signal-to-noise ratio advantage of a directional microphone is achieved by reducing the sensitivity of the microphone to sounds from the sides and back. A fully adaptive directional microphone (one that automatically switches between an omnidirectional mode and various directional polar patterns) may allow the achievement of signal-to-noise (SNR) improvement with minimal loss on audibility to sounds that originate from the sides and back. To demonstrate such possibilities, this study compared the soundfield aided thresholds, speech in quiet at different input levels, and speech in noise performance of 17 hearing-impaired participants under three microphone modes (omnidirectional, fixed hypercardioid, and fully [or automatic] adaptive) as the stimuli were presented from 0 degrees to 180 degrees in 45 degrees intervals. The results showed a significant azimuth effect only with the fixed directional microphone. In quiet, the fully adaptive microphone performed similarly as the omnidirectional microphone at all frequencies, input levels, and azimuths. In noise, the fully adaptive microphone achieved similar SNR improvement as the fixed directional microphone. Clinical implications of the results of this study were discussed.
authors.affiliation: Widex Office of Research in Clinical Amplification, 2300 Cabot Drive, Suite 415, Lisle, IL 60532, USA. Fkuk@widexmail.com
authors.forename: Francis
authors.initials: F
authors.lastname: Kuk
authors.forename: Denise
authors.initials: D
authors.lastname: Keenan
authors.forename: Chi-Chuen
authors.initials: CC
authors.lastname: Lau
authors.forename: Carl
authors.initials: C
authors.lastname: Ludvigsen
mesh_terms: D000161:Acoustic Stimulation / Q000295:instrumentation; D000368:Aged; D000369:Aged, 80 and over; D001309:Auditory Threshold; D004777:Environment; D004867:Equipment Design; D006310:Hearing Aids; D006801:Humans; D008875:Middle Aged; D009622:Noise / Q000009:adverse effects; D017755:Prosthesis Fitting; D013067:Speech Perception