X-Fi - stereo speakers + extra sub?

[Blind Man]

alright, atm I have just got a sub to go along with my stereo speakers, however when I select 2.0/2.1 in the audio config it doesn't show a port to plug the sub into and I don't get sound from the sub anyway, if I switch to 5.1 it does show where to plug the sub into and I will get sub sound, best I can do atm is leave it on 5.1 and move all the audio to the front but it sounds really really bad and distorted on some songs, any ideas? (I have an X-Fi Xtreme Music)

 

[Uncle Jim]

5.1 is the only way to get a separate channel for LFE as far as I know.
Make sure front speakers are in out 1 not out 2. Turn the crystallizer and CMSS-3D off

 

[Blind Man]

speakers are in line 1, I turned the CMSS-3d off and the sub turns off with it however