Currently I have onboard sound with the ALC889a chipset and I primarily use my headphones for 90% of the time I'm at the computer. The onboard sound will downmix surround sound sources (quad, 5.1, 7.1) to stereo, but the virtualization is non-existent (can't tell the difference between front...
To begin, I've had the same problem occur in both windows and while attempting to install linux so I believe this to either be a firmware or hardware problem.
Now as to the problem itself. Nothing to the system has been modified since I built it two months ago and this problem just appeared...