posted 09 December 2000 02:32            

Anyway, I have some moderate to severe hearing loss starting at 1.5 KHz or so, but I still like to mix and make music. I decided to put a SHARC proto-board I had laying around to good use and made a hearing compensation filter for use between the mixer and my headphones. This allows me to mix for normal people, without introducing unwanted EQ into the mix. And the audience gets to hear what I now get to hear -- normal sound!

Hearing aids are cumbersome with headphones and they tend to squeal with feedback in the tight cups. The system works great -- 48 KHz, stereo, with independent compensation for left and right. There is plenty of compute time remaining, so I will probably also add some dynamics processing (compression and noise reduction) and soft saturation to avoid clipping.

The code is absolutely trivial to produce using a filter design code I wrote this evening. If anyone else is interested in this I can make my system description and code available to you.

Good digital hearing aids that can accomplish spectral whitening like this cost around $6K a pair, and they are not reprogrammable by the user. My little proto board system cost around $200 back when I bought it and the code is free...