I have no problems with my users added to the "sys" group. Then again, I am using an AWE64, not a SB Live. I would suggest trying putting a user in the "sys" group, and other than that, I don't know. I have noticed that the sound support on some cards in Linux is dodgy. For example, the Intel I810 chip that comes on a lot of newer computers as an on-board sound card is absolutely terrible! I suppose that's why Alsa was invented. It's a shame the kernel team couldn't get with the Alsa team and give the stock kernel some really good sound support.
