The only way I can get sound out of my rear speakers is to select an
Environment under
Sound Effects in the
Realtek HD Audio control panel. The sound was working fine yesterday (fresh install) without an environment selected. The only down side to this is it adds a bunch of reverb and muddles the sound. I am running on a GA-EP54T-DS3R, using the drivers downloaded from the realtek site.
www.realtek.com
In my opinion I shouldn't have to select an environment to get the sound out of the rear speakers. very frustrating.
Hope this sheds some light for someone.