Frye FONIX 7000 User Manual
Page 195
The FONIX CIC Feature
187
Knowing the physical volume of the occluded ear canal and its frequency
response variations, it is possible to calculate the equivalent volume of the TM
itself at each frequency and to apply this figure to the response of the 0.25 cc
cavity between the hearing aid and the TM.
When the calculated volume variation of the TM is applied to the smaller vol-
ume of the CIC coupler, the total response variation comes out to be from -8.6
dB at 200 Hz to +5.5 dB at 8000 Hz for a total variation of 14.1dB.
Summary
Using the CIC coupler with its software option gives the dispenser an immediate
idea of how much gain that this new type of hearing instrument is going to give
the hearing impaired individual. It is nice to see that the CIC hearing aid can
really produce significant amounts of gain in spite of its apparently poor perfor-
mance in the 2cc world of the ANSI standard test.
The user must remember that an actual ear may produce differences from the
predicted values.
Acknowledgment
Mead Killion, Mahlon Burkhard and Elmer Carlson are to be thanked for help-
ing assemble the data from which the CIC corrections were derived.