SPDIF is different with x-fi
It makes very little sense to use the x-fi with spdif out for playing games, music, etc.
While you can play movies through the spdif out and it will appear as "dolby digital or dts on your receiver", thats about as far as creative will go towards spdif.
To sum up- the spdif - Sony phillips digital is designed to carry digital data so that some device can process it and then play sound. For example, a dvd player will have the receiver do the 5.1 sound and or if you hook it up the x-fi then the x-fi will decode the sound.
The X-fi doesnt use dolby digital or dts when you play games. It uses EAX which is its own kind of surround sound. As such if you want to use eax or cmss3d you need to use your recievers multi-channel input to get the benefits.
Think of the x-fi as its own kinda of audio processor. Getting back to the subject- the x-fi can do a couple things with the SP/DIF connector.
The first its to output dolby digital or DTS to the receiver just like ur dvd player would or cable box to ur reciever's optical or coax in. The second is to output 2 channel PCM- kinda like those wav files data to the receiver.
In both of these cases the x-fi is just transmitting dats to the receiver, its not doing any processing
The solution for you may vary depending on what receiver you have.
One solution is to get something like the sound blaster home theater cable or get 3 male stereo to female rca cables, (a good one is the sonicwave 3.5mm to female rca connector) and use rca cables to plug it into the multi-channel in in your recieer.
A more practical solution would be to get 3 3.5mm stereo to male rca cables if you can do that.
Go to
www.impactacoustics.com and look at their velocity and sonicwave cables.
If you cant do that then your out of luck as you cant use the x-fi to output to your system. However, Creative does sell something called the dts-610 which can output DTS surround sound to your receiver from the sound card itself.
You might lose out on some of the detailed sound, but it would work on your receiver and it would be just as good as playing a DVD MOVIE in surround sound.
Again, though the spdif out won't help you it just transmits data from a program such as movie or maybe a few games that use dolby digital but almost all comp games use EAX as noted on the logo.
Message me with more questions and answers, glad to fill in the buzz.