Hey everyone, 
I am running a 790i ultra , with a  Xeon  and 8gb of Crucial DDR3-1600.
My speakers are a set of logitech z-5500 5.1 capable of DTS and Dolby Digital playback.
 
Sound works fine when outputting stereo.
issue: I cannot play 5.1 sound
 
When i try to play DTS audio or Dolby Digital samples i get no output at all.
This happens both on movies with 5.1 sound and every time if i try the samples of windows 7-64bit (right click on taskbar speaker > Digital Audio (s/pdif) > properties > Supported formats tab > select either DTS or DD and hit test, i get no sound but my speakers do automatically indicate the appropriate format)
My (z5500 logitech) speakers do realise they should receive something digital and indicate the appropriate message (DTS or Dolby) on their screen but produce no sound.
 
Notes (i dont know if its relative but have it anyway):

• I hear a quick "sqweek" when i play a song (stereo) then try to test the DTS or DD samples of window - then silence.
• There is a list of "default formats" in digital output properties >advanced tab where all i get is 2 channels and different bitrates and hz - No more channels shown. (same list is in the Realtek HD audio manager > default format tab)
• The speakers have a choice of "effect" where you can select between: stereo, stereo x2, DD PLII movie , DD PLII music. I only get sound when the effect is stereo and stereo x2, DD PLII movie and music are silent.
• Within the Realtek HD audio manager, there is no screen to set up individual speakers, only effects and other crap. Shouldn't there be such a screen? or does it only appear with 6ch direct connection?

 
I have the same issue both with Coax and Optical out.
I have tried the evga site's realtek 2.68 driver and the official realtek 2.80.
I have not tried the 6 chan direct connection (3x stereo jack cables) as the pc is far from the speakers. 
 
 
I ran out of options, so i am turning for help to the community.
Any ideas to test out would be greatly appreciated,
Regards, 
k.
 
 

Check out this thread and see if this can fix you up: : https://www.techpowerup.c...ts-interactive.193148/ Just remember to clean out the old driver first and install the full package. Let us know what happens.

Unfortunately the digital output for the Realtek chip on this motherboard is only capable of 2 channel sound. In order to support Dolby 5.1, you would need to use the analog connections. I'm sorry for the inconvenience.