Anybody know about soundproofing a mac?

Put the machine inside a typical (large) rack box, leaving one end open for circulation. The boxes are usually padded on the inside which helps. Make sure the open end isn't pointed at your mic or any hard reflective surface. That works for me. I do this even though I do have an isolation booth. It makes for cleaner listening.
RW

I have a MacPro Jan08 8 core and it's virtually silent.

i am also running a macpro 2.66 (2009) and have to say that it is pretty darn quiet to begin with and once i am monitoring at any volume the machine hum just fades away all together. some of those isolation units are pretty good also.... a sound engineer that i know just runs the computer to a closet that he has simply sound-proofed the door of w sonic foam....when the closet door is shut...voila - silence. the closet is large enough that air flow is not a problem.

jefff

Can you tell us exactly which model you have?

(BTW, you can add this info to your profile so you don't have to keep saying it…)

Well then, I don't think the noise should be too bad. You could easily built a box for it, but obviously if there isn't enough flow of air around it then it will overheat. And air conditioning would be a lot noisier than the Mac!

You won't need dramatically effective soundproofing to make a big difference. I find that resting the Mac on several mouse mats is an excellent way to reduce transmission of vibration through surface contact; for me, that's all I need to do.

I used my Mac Pro (early '08 model) in a small college dorm room for a while, and never had any serious bleed issues with it. Sometimes I put a chair with a blanket draped over it between the Mac and the mic, but that was about it. I wouldn't be too worried about it.

Of bigger concern would probably be any external hard drives you might have. I get a lot more noise from them than my Mac, but they still don't get into my audio much with the above mentioned method. Of course, if you have externals that aren't being used during tracking you can just turn them off--this is what I do with my Time Machine drive.

My Mac Pro makes enough noise to be a problem when tracks are stacked or when recording very quiet sources...voice overs, etc. I simply cut a small hole in the wall to the other room and put the tower there. That solved my problem completely.

As mentioned by others the Mac Pro is reasonably quiet.

It really depends what you are trying to record and how, but I would have thought that other sounds e.g. traffic noise, etc. could be more of a problem.

When recording try to ensure that the null point of the microphone is pointing at the Mac Pro to reduce the amount of Mac Pro sound you'll get on the recording. Using a mic like a Shure SM7 for vocals pretty much solves the problem of unwanted sounds getting onto a vocal track.

Remember that when recording using a sensitive condenser mic it may pick up sounds like the Mac Pro, but what's more significant is the sound of the room that the mic will pick up. E.g. if you are recording acoustic guitar you're actually recording the direct sound coming from the guitar and the sound bouncing around the room. If you aren't working in a room that has been treated to cut down unwanted reflections, then what you record won't sound very good so the minimal sound from the Mac Pro will be the least of your worries.