bicros hearing aids

HearWHAC HearWHAC at netins.net
Sat Nov 11 14:43:18 EST 1995


In article <480bfp$bk8 at hollywood.cinenet.net>, erc at cinenet.net says...
>
>
>The way I understand it, bicros hearing aids use each other's
>microphones instead of their own.  Is that all that's meant
>by bicros?

Not at all. Your explanation of "bicros" implies a "cris-cros" or "double 
cros" arrangement with a mike on each side of the head feeding to receivers 
on the opposite sides of the head. A "bicros hearing aid" has microphones on 
each side of the head, but they both feed into one receiver feeding into 
only one ear. Most bicros setups have only one amplifier and one volume 
control. However, several manufacturers make a "deluxe bicros" which has two 
amplifiers and two volume controls (one on each side of the head) that feed 
into one receiver into one ear.

>Is the only purpose to reduce feedback?

Not at all. A "cris-cros" or "double cros" setup actually causes more 
feedback, not less. Thus, it is never used! A "cros" hearing aid can be used 
to reduce feedback. I fit several thousand "cros" hearing aids in the 1970's 
and early 1980's for two different reasons: (1) it allowed me to fit an 
"open ear" fitting without feedback which is most useful for high-frequency 
hearing losses and (2) it could also be useful for power ear-level fittings 
where having the mike and the receiver too close together caused feedback 
problems that could not be solved with tight-fitting earmolds. Both of these 
uses were quite effective, but the down side is you cannot do a binaural 
fitting.

>Are there a lot of hearing aids that can be configured that way?

I believe Rexton and Telex still make eyeglass bicros/cros hearing aids. 
There may be others. A number of companies make BTE and ITE cros hearing 
aids. Telex even makes a wireless cros/bicros aid with a BTE on one side and 
ITE on the other side. Starkey makes ITE cros and bi-cros aids and I am sure 
there are others. I suspect that most of the European BTE companies still 
make cros/bicros configurations.




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