I thought this was a RealTek issue, but on further scientific experimentation, I realize this is only an issue in StreetDeck.
Here is my post from the sound section, Odd Sound Question - Realtek resets audio ports
but a quick rehash
Sounds working great in streetdeck, restart, no sound in streetdeck. open up the realtek panel, and hit 3d audio, and audio plays fine all the way around the car. Open up winamp, centrafuse, riderunner, iTunes, or any other audio application and it works fine (all 5 channels). Open back up street deck and no sound. Usually with a great amount of playing around (going to windowed mode, and pllaying with many volume oiptions and different programs while in windowed mode), I can get street deck to play SUB and FRONT speakers only, but no rear playing. Kind of annoying esp since StreetDeck is the only app I have that will play the rearview camera, and has good visuals.
Any one have a similar experience. We are running TinyXP, however I like to think it is not a windows issue when sound works perfect in every other program.