oops, forgot to update this... I got an answer with the help of Sonicxtacy02.
Basically, the USB-SA soundcard would have to be selected as the recording device, and the onboard (or whatever soundcard you have) would be the playback device in Windows Sound Mixer. Line-In and Line-Out should be okay, but the mic port on the onboard soundcard becomes useless.
There goes my auxiliary input plan. I'll probably integrate an FM transmitter for aux devices.
original post:
Quote: Originally Posted by
Sonicxtacy02 
i have the andrea mic's 3.5 inch line running to their sound adapter which is connected via usb to the pc. All of my outputs come from the onboard HD audio. So in windows sound mixer i selected the andrea sound adapter as the mic device and kept the playback device as the onboard audio. If you do this and keep the andrea software running in the background, noice and echo cancellation works. The only time it didnt work for me is when i hibernated and the mic resumsed as another device... but i fixed that problem by hooking the andrea sound adapter to the carnetix p5usb device from mp3car