Have you checked to make sure the connections between the device and your speakers is sound?
To make sure alsa is set up correctly do:
Code:
"alsamixer"
"F6" and select Creative Labs SB X-Fi
Navigate to Master
"m" to unmute
And use the up and down arrows to change volume
Check to make sure alsa is using the correct sound device drivers by cating /proc/asound/modules. You should be using snd-ctxfi.