Little by little chipping away at what I'll need to get going here. Came across a new problem, unfortunately.
I've encountered, what appears to be, a ground loop static-like buzz emulating from my iMac when hooked up to my mixer and active powered speakers. Not a steady consistent hum or buzz, but one that seems to worsen when you're actually doing something on the screen, i.e. moving the mouse or if you're on a web page where flash images are rotating/changing.
If you're scrolling down a web page the static buzz will coincide with that.
The problem is evident if I use the headphone jack on the mixer as well, though not evident if I plug a headphone straight into the iMac.
I did a search of the problem in Google and came up with a few chat forums discussing the issue. Some seemed to eliminate the problem by plugging various components into different outlets (did that, no luck), plugging everything into the same outlet/power strip (did that, no luck), or even connecting the 3 prong AC plug of the iMac to a 2 prong plug (Not recommended but I did that and it resulted in a steady hum instead). Some claimed success after purchasing a ground loop isolator (Radio Shack or Hum X), which I'm considering, though I'm wondering if there's some simpler solution I'm overlooking. I also read that it could be the iMac's Firewire 800 port that causes it, though I didn't hear a difference when disconnecting my Firewire hard drive. If it ends up being the Firewire port, I will be pissed, since that potentially renders my port useless if I'm trying to track cleanly and may force me to go with a USB interface instead.
So, anyone encounter this problem before and remedied it?
P.S. On another note, I sent over my basement layout/dimensions to Auralex via their "free personalized room analysis form". Hopefully they'll get back to me with some recommendations for proper placement of sound proofing panels (though I won't be getting Auralex panels).