Bought a Roccat Kave and an X-fi 5.1 Durround external soundcard recently, but have 1 or 2 issues.
For starters the Sub fader on the kaves controler doesn't work and some sounds sound kind of tinny, to give an examle from recent experience, the background noise in the CIC in Mass Effect 2 and the rain on the planet where you undertake Jacks sidequest.
I have exactly the same problem and the same soundcard. I have tried every possible solution/setting, i.e switching center/sub, Changing sound lvls etc. And I cant get the "bass/sub" to work properly : (
switching center/bass: makes the "bass" effect i want and it is said to have, but the downside is that i lose the center effect so speech in oblivion becomes very deep and not very loud.
not switching them: makes all sounds realistic but i dont get any sound from the sub in any games, but the center front and rear works perfecty.
It's verry easy to get this to work.
I had the same problem.
Install all the software for the X-fi soundcard.
(Creative start console) .
There you see your speaker configuration.
Click on Bass (left side) and you can turn on redirect bass.
Put your Crossover frequency to 150 Hz, and put on +15 Db and it works great.