ALSA/Audigy Multichannel Setup Old
From Rivendell Wiki
I have an Audigy 1 card that I wanted to be able to use the surround outs as a separate output on my board. After messing with my .asoundrc file, here's the config that worked.
pcm.rd0 { type plug slave { pcm "front" } } ctl.rd0 { type hw card 0 }
pcm.rd1 { type plug slave { pcm "rear" } } ctl.rd1 { type hw card 0 }
I believe the "rear" and "front" keywords are unique to the Audigy emu10k1 driver, not every Alsa card driver will include them.
I also came very close using the Alsa dmix plugin, but the output from Rivendell was unusable.