Will my 7.1 audio supported MOBO make a 5.1 audio headset 7.1? I'm pondering about buying a Sennheiser HD 280 (5.1 audio) and I saw that you can buy a sound card to make it 7.1. I have a MOBO that can already handle 7.1 audio, so will that make the HD 280 sound as if it had 7.1 audio?