I’ve been wanting surround sound in Linux for a while. My XP machine at mom’s flips stereo to the back, which I really like. Thanks to the Ubuntu forums, I found that I had to uncomment the default-sample-channels line and change it to 6 for 5.1 sound. (5 speakers + subwoofer) I also changed the sample rate because I noticed it complaining in the PulseAudio logs (it was changing it to the correct value) while I was fiddling with getting it working, but I don’t think that’s needed. I added myself to the pulse-rt, pulse, and pulse-access groups. It still wasn’t working, and I was getting upset. I found this post, and sure enough, the volume on the other channels was zeroed out in the volume control. I set all my sound output preferences in System > Preferences > Sound to PulseAudio Sound Server, but when I put it back to Autodetect it still worked. I’m happy now.