I'm running out of ideas on how to troubleshoot this. I don't suppose anyone here has had the misfortune of dealing with a SB Live card under Linux? Normal playback from file or CD sources works fine, but I don't hear anything if I plug in a source via the SB Live's "line in" jack. I've had no experience diagnosing audio hardware trouble under Linux, so I'm not even sure what to look at to narrow the problem down.