[LAU] audio compression of all alsa output?

[Nathan Curry]

I've got a system I'm doing tech support on, and I'm trying to get all
audio streams normalized/compressed before the audio is spit out the
speakers.

Basically, we've got several buttons that play an audio stream through
mpg123.  The streams are different volumes and that understandably
upsets the customers when they change audio streams and it's suddenly
blaring christian contemporary music at their patrons.

Does anyone know of any way to do this, or at least any little
compression/normalization apps I might be able to pipe the data
through? I would prefer to avoid JACK, but that's only because I don't
want to have to do more work than necessary, and this isn't (rather,
shouldn't be) a very complex system.

Any input would be appreciated.  Thanks.
-Nathan
PS: This godawful thing is running on FC4 (vanilla, for all intents
and purposes), btw.