Having a little trouble setting up my Pearl Throne Thumper. I use headphones mainly (do have speakers connected via a splitter that I sometimes use for YouTube etc). If I remove the speakers and put in the Butt Kicker then the right speaker in my headphones is a lot quieter than the left. My windows settings are on stereo (but it doesn't matter what it is set to there is no difference). I use on-board sound. If I plug it into the centre/sub socket and change settings to 5.1 or 7.1 then it works fine in the realtek demo but not in game. What have I done wrong? Would I need a separate sound card?