Hello!
Finally I've found some time and coded a small wrapper (based on
artsdsp) to hear the sound from Enemy Territory on my Delta66.
Actually it routes the sound through JACK, so it may be useful not
only for poor Envy24 users :)
I hope it should work for all Quake3-based games.
Feel free to try it out and send your comments.
Hope it'll help somebody besides me.
The link:
http://www.konstruktiv.org/q3jack/
Cheers!