Looking for Linux buffs.

[Domo-Kun]

I have a dual boot Windows xp/Ubuntu set up on this PC.

However, I'm using an ATI Radeon HD 4830 with HDMI to an HDTV.

I have video, but no sound, I have all of my sound output set to HDMI under system preferences, but it still doesn't play any sounds.

I updated all of the proprietary drivers, and set up the catalyst control center for the video card, too.

 

I have no idea wtf the issue is.