I might not have a direct answer to the question, but if this is your sound card ---> "Creative SB Live! 5.1 Digital (SB0220) Sound Card", it is an OEM sound card, (Dell), and even drivers for Windows is hard to find, you won't even get Windows drivers from Creative. Dell has tweaked this one a little and it is out of the ordinary.
Can't hurt to try command:
$ amixer set Master 100% unmute