Set up pc audio for 5.1 home theater

[mitzaotomitza]

I have a msi big bang x79 with both optical and sdpif.
I hant to connect it to my bose 5.1 H.T to the Aux input.
For a reason there is no audio out. I updated the realtek driver and still nothing.
What do you thing I am missing here.
I tried to get the audio from my nvidia660ti card and still no luck. This card should deliver audio through hdmi cable.
Do you thing that there might be a conflict between the nvidia audio and msi realtek ???

 

[fralexandr]

are you using a bose ht set with onkyo HT-RC440 receiver?

did you try changing the receiver's input?
http://onkyo-audio.pl/uploads/files/ins/amplitunerykd/HT-RC440.pdf
page 41 shows how to set up inputs

do you happen to have a TV or display that supports HDMI?
it might be easier to test with a dvd/bluray player, roku box, or game console and TV.