Field-to-microphone transfer functions for completely-in-the-canal (CIC) instruments.
OBJECTIVE
To measure the field-to-microphone transfer function for two sizes of completely-in-the-canal (CIC) devices, at two loudspeaker azimuths.


METHODS
Field-to-microphone transfer functions were measured for both standard- and micro-CIC instruments, at 0 degree and 45 degrees azimuth, in a sample of 24 adults. This was accomplished with custom instruments, which allowed for a direct connection between the CIC microphone electrical output and the measurement/analysis instrumentation system.


RESULTS
For the standard-CIC, the peak in the average field-to-microphone transfer function was 8 dB at 4000 Hz for 0 degree azimuth and 13.7 dB at 5000 Hz for 45 degrees azimuth.


CONCLUSIONS
The results demonstrate and define, at two signal azimuths, the acoustic advantage of the CIC microphone placement relative to that reported for alternative hearing aid styles.
Cornelisse
L E
LE
Department of Communicative Disorders, University of Western Ontario, London, Canada.
Seewald
R C
RC
D000328:Adult; D004424:Ear Canal / Q000502:physiology / Q000503:physiopathology; D005260:Female; D006310:Hearing Aids; D006801:Humans; D008297:Male