Newbee wants to kick start - encrypted calls

[Ian Stirling]

Crane, Matthew wrote:
> Not sure if there's a specific project, I'm hoping to do some sort of
> "analog" encryption, with audio effects and inverse effects, such that
> it does not need to be digitally decoded, where the excellent pattern
> recognition engine in the brain does most of the work.
> 

You can't do much.
It has to 'sound' voice-like to the multiple codecs in the signal chain 
of a GSM call, or the codec just discards the sound.

Listen to a voice over a good GSM line.
It's quite well reproduced.

Now, listen to an assortment of music.
Some will come out quite well, and be reproduced much like they came out.
Some are utterly shredded.