I couldn't find any mention of this on the net so I thought I may as well post it. The soundblaster X-fi has a jack on the back that they call the "flexijack." It doubles up as a coaxial digital out if you buy a mono minijack to phono coaxial cable you can use it on Linux.
I couldn't get any sound out of it and was about to give up until I managed to unmute the digital out using this command:-
amixer sset 'Digit-IO',0 unmute
The digital out is okay but not in the same league as a m2tech hi-face async usb to coaxial converter that I tried it against.
