So I just got a pair of Sennheiser HD 558's, as well as a used Asus Xonar DX sound card. I will not be using a speaker setup with the card, only the headphones. Do I have to disable the audio drivers in my motherboard BIOS in order to take advantage of the sound card? And will disabling that affect the use of a standalone microphone down the road, since the USB input will have to be plugged into the motherboard?