The 'sound' of the iMac?

Question

I'm helping a friend set up a small recording studio with his brand new 30" iMac. I notice there is a faint 60 cycle-ish hum coming from the otherwise silent creature.
Is this basically the 'running sound' of the new iMac or, if I do some finagling with the wiring, might I be able to quieten it further. It sounds like the sort of hum one would pick up from improperly grounded wiring ... though we are not talking about what I'm hearing through its speakers; only what I hear as I hover over the beast.
I'm aware this may seem a bit dumb ... but if one never asks, one is never quite sure...
Ben

Answer 1

Hey RC - R,
How does one 'quote' the incoming post (I know there is a button or keystroke somewhere), so that questions can be answered without confusion? In the meanwhile, I will indent my answers:
Where is the iMac in relation to the mic?
Mic is three feet in front of screen... aimed away from the screen at the 'voice'.
Is the mic a cardioid or omni pickup pattern?
It's a Neumann directional (very nice mic)
Is it suspended in an isolating mount?
It's on a standard mic stand ... not touching the iMac desk. I'll check around and see if they got some kind of proper holding device with the mic.
Can you increase the distance between the iMac & mic, just for recording? How far is it to the surfaces behind & above the iMac?
Not touching the surfaces. Can't move it further away, coz he needs to be working with the iMac simultaneously.
There should be very little sound coming off the front of the iMac; most of it should be reflected off the surfaces near it, plus a little transmitted as vibration through the surface it is placed on. Can you place a low baffle between the front of the iMac & the desk (or whatever the work surface) & maybe set everything on a sound deadening mat? Everything will be magnified if the gain is cranked up & a compressor is used in the recording chain to control level, so see if that is an issue.
The iMac is sitting at the back of a soundbooth we just built, lined with acoustic foam. Nice little booth that covers the entire work table, a little house, nice but for the 'hum' of the iMac. No vibrations are being transmitted to the mic (other than sound vibrations). I'm going to see if I can build a little acoustic foam baffle around the back of the mic; try a gate on the recorded voice if need be; or train the guy to use his perfectly good Zoom, and put the iMac to sleep every time he has to record a line.
The recordings are never going to be totally silent if the mic & iMac are in the same acoustic space, but with attention to detail you should be able to get pretty quiet results. If not, all I can suggest is getting an external monitor & moving the iMac to a more isolated spot for recording sessions.
If only he had bought a tower instead of the iMac. It's such a beautiful screen though. Mmmm. I bet for $300 we could get him a good Samsung to place in the booth, drop the iMac to the floor below, and then only bring the iMac back up when he has to do the color correction and post production - which is only done at the very end, and which I will be helping him with.
So that is another good idea. I'm meditate on it a bit. Dave has just blown a nice bit of cash on making the sound booth, getting the new iMac, plus a Canon SLR that does HD ... another monitor might just be the straw and the camel thing.
Thank you mucho for your good advice...
Ben