Sound output problem Logitech z906

[cyber.leo97]

Well I have had my share of troubles with those speakers but they are still so damn good I'll never let them go. So the issue I'm having now is as follows: As some of you know, the z906 supports digital optical input, and so it happens I have a motherboard that has an optical output as well. Some dollars later I get myself a cable and set it up. Everything seems to be normal except when I'm running from optical I have only the 3 speaker settings 3D (basically simulated 5.1 surround), 4.1 and 2.1, with the true 5.1 option not working (the option where no orange led is lit from the STEREO section on the console). Now this is a problem I have come to accept, though I would like to know why it happens or if it can be fixed. But my other problem is the main suspect. In the Realtek driver menu on the "Default Format" tab I can select different frequency settings and such, but the last setting is the DTS Interactive (5.1 Surround). When I select that, the DECODE LED lights up and I can no longer change the STEREO section. But while in this mode the speakers only work in 2.1 (LFE + 2 Front Satellites). Is there something I can do to have 5.1 while in DTS mode on optical connection?

 

[Colif]

I have those speakers, and found same thing.

See if anything here helps -
http://www.tomsguide.com/answers/id-3534487/logitech-z906-digital-optical-sound.html
http://www.tomsguide.com/answers/id-3634253/logitech-z906-decode-light-speaker-turn.html

You can get 5.1 through analog connection but not digital. You may need a receiver to get actual 5.1 through digital

its not a realtek thing, iIt might be a hardware thing. Can motherboard output a DTS signal?

at least you know 5.1 is when it shows no lights, its not mentioned anywhere in the instruction book