Judging by a few reviews I have read on sound cards, S/PDIF pass-through seems to confuse a lot people. When using S/PDIF pass-through, the sound card does not process or alter the digital signal in any way (hence the term "pass-through").If you are getting signal at the S/PDIF output, the card is doing it's job. To get Dolby Digital 5.1 at the S/PSIF output, your software player needs to be set up to provide a 2-channel digital signal to the S/PDIF output (the Dolby Digital 5.1 signal is encoded into the 2-channel signal). The signal is decoded by your processor or receiver, converted into an analog signal, and passed on to the amplifiers/speakers. If your mobo has an S/PDIF header you don't even need a sound card to do this, just a 35 cent cable and an adapter card (Asus makes one with coax and toslink for about five bucks).