Comment 8 for bug 40732

Perhaps this can help. To get 5.1 playback for everything, I created an .asoundrc in my home dir with:
pcm.!default {
type plug
slave.pcm "surround51"
slave.channels 6
route_policy duplicate
}

After that, everything will be in 5.1 , however GStreamer gave heavy ticking in the sound. Totem-xine, xine play fine now. (ticking sound was reported as a bug http://bugzilla.gnome.org/show_bug.cgi?id=365429 )