I've got a quick question about the Mac Pro's audio outputs. can audio play through both the optical output and analog output? say i hooked up a 5.1 speakers to the optical output and then headphones to the analog output. would audio play through both? or could i at select which to output to through system preferences? because I like really clean set-ups and it would be cool if i could choose which to use without plugging and un-plugging cables all of the time. thanks.