Onboard works fine, but I do want my soundcard to work properly and the ADC in the onboard soundcard is not that great (meaning my voice will sound different).
Yes, 100%. And like I said, using Direct Sound works perfectly fine, but when I try to use programs like Teamspeak, Xsplt or EG the in-game voice in ArmA 2 the volume is very low. Steam in-game voice however does work.