Hi guys. I have the same problem. Did you solve it ?
I had a sound issue with the motherboard. I fixed it.
I have a 5.1 speaker system. Logitech computer speaker system with a bass and some speakers.
I simply matched the three plugs coming out of the speaker system with the same colored holes in the motherboard's audio ports.
This did not work. No sound came out.
Then I looked in the motherboard's manual to page 2-27, and it shows how the different speaker systems are supposed to be connected to the motherboard. The colors of the plugs and holes DO NOT match up, nor are they supposed to.
Once you have everything plugged in according to the manual, open up the realtek HD audio manager that you installed from the disk, and under speaker configuration, select the type of speaker system you have. After selecting the proper configuration, hit the play button to test each component and make sure it's all hooked up correctly. Unmute everything, turn the volume up, make sure the speakers are on.
Make sure to set it as the default device too.