hi guys i bought z906 few months ago and connected it with optical cable thinking its the best option when it comes to quality surround. what i noticed the i cant select more then 2.1 channels in windows and realtek audio manger and i can only select 3D, 4.1 or 2.1 and decode option is not lighting up. then i plugged it in with the three cables and now i can select 5.1 in windows and realtek but when i test play the sound only two speakers go alive the i deselect all the option from 3D, 4.1 and 2.1 then i get better result and 4 speakers work but no matter what i do the rear right speaker is not working. i checked the speaker and it is working fine on 3D and 4.1 so its not the speaker. my mainboard is Z68 Extreme7 Gen3 i hope i get it sorted dont really know what else to do