I started off trying to run Pale Moon browser as user "spot" in SULU2. The video worked, but there was no sound. I ran "alsamixer" (again as "spot") but it died, complaining about not being able to find the mixer. The problem was that all files in /dev/snd were root-accessable-only. The solution was to execute (as root) the command...
Both sound and alsamixer work for "spot" now. Files in /dev are virtual, and are re-created at bootup, so it's best to add the above command to /etc/rc.d/rc.local which is run at the end of the bootup process.