This is a pretty weird occurance for me. I've run into alot of problems concerning sound, but none like this before. My sound is working fine, it's crystal clear, it's just the right volume, but the problem is it's lop-sided. By that, I mean there is no sound coming out of the left side. It's like if you had the balancer set all the way to the right. (no, I don't... I checked with aumix numerous times.) Honestly, I have no clue where to begin with this... or if it should even be in the hardware forum. Hehe.

Set-up: Gentoo on 2.4.26 kernel (uname -r == 2.4.26-gentoo-r9), Sound Blaster Live! sound card (emu10k1 module), using the aumix mixer. Problem persists in mp3blaster, xmms and mplayer (both movies and mp3's.)

Edit: After putting my two left speakers to me ear, I've found that they are putting out sound... they just aren't nearly as loud as my right speakers (so quiet that they have to be next to my ear ). Weird...

This is going to sound stupid, but it may just be the cable or the connector. Try twirling the plug around a little where it connects into your sound card. (I've got the same exact issue with a pair of headphones - they work just find, but usually the left side is close to silent. Spinning the plug around a bit fixes it, so in my case there obviously must be something wrong with the connector somehow.) -- J.W.

I did that and still no improvements.
More info on my set up: I have 4 speakers and one subwoofer, the two front channel speakers are connected to one plug while the rear channel speakers are connected to another on the sound card. The audio still doesn't work when directly playing a cd through my cd-rom drive (a cable connects the drive to the sound card) so I'm going to reseat my sound card and see if that works...

Edit: reseating didn't do it. =(