I have a pair of Astro A40s that I use for my xbox 360 hooked up thru toslink. It has a MP3 input in the back of the mixamp that I have my PC hooked up to that so I can here skype and stuff while Im gaming. I have a little issue with that though. Im pretty sure you cant get 7.1 out of a mp3 cable but the mixamp does it. The issue is that when I have the 3.5mm cable in the rear input I only get stereo in the Realtek test. When I have it in the front Im able to hear all 7 channels (expect bass). Anyone know why this is?