No Rattle Just Hum

When recording, how do I keep the condenser mic from picking up the computer fan sounds?

I can hear the noise from my computer's fans on my vocal takes. I can kill the noise during the silences with a gate, but it's still there in the vocal parts muddying things up. I don't have any kind of sound treatments or space for them. I'm using a condenser mic. There's a simple way to deal with this, right?

posted by chrchr (7 comments total)

Make louder music!

Okay, fine, if that isn't an option, there are a few things you can try.

Your mic probably has a cardioid pickup pattern, so it will do best at rejecting noise 180 degrees from the front of the capsule. Move it so the back of the mic directly faces the computer.

If that's not enough (which it won't be), you can try hanging a blanket between the mic and the computer to eat up some of the fan noise. The downside is that this might have a negative effect on the tone of your vocal take. Try it and find out.

You could also (and this is a bad idea) wrap the computer in something to suck up the sound, or put it inside a box. Your computer will overheat if you do this. But if you remove it between takes, you might be able to get away with it.

Of course, you could just deal with it, stick a high-pass filter on the vocal tracks (which you should be doing anyway) to eat up the rumble, and deal with the whine.
posted by uncleozzy at 8:15 AM on January 14, 2011 [1 favorite]

I don't how helpful this is, but some DAWs have a tool that allows you to take a sample of that noise (like when you're not singing but still getting a signal) and eliminate it from the entire track.
posted by snsranch at 10:59 AM on January 14, 2011 [1 favorite]

In my (admittedly limited) experience, that kind of noise reduction leaves enough artifacts that you'd notice it in a mix sparse enough to need it in the first place. (It's been a really long time since I've tried, though, so presumably it's gotten better, or at least faster. It's certainly worth a try.)
posted by uncleozzy at 11:12 AM on January 14, 2011

I eventually solved the problem by investing in a better unidirectional mic, and using a section of dense particle board as a noise shield. I just lean the board against the front of the machine and it absorbs/deflects the sound significantly (I always intended to build an L-shaped shield that can stand on its own in front of the computer, but I'm lazy).

DO NOT completely enclose your computer in anything.
posted by scottandrew at 1:26 PM on January 14, 2011

The simplest solution is to buy a piece of 5/8" plywood that you can place between the computer and the mic. Drape a heavy blanket over it. A box of the same stuff with an opening at the back for air circulation will muffle the noise almost completely. But the single sheet will get you a long way.

I used this tactic to muffle a generator on location when shooting a documentary.
posted by unSane at 7:31 PM on January 14, 2011

(a single heavy blanket will not do much -- the key in muffling sound properly is mass. It is easy to mitigate high frequencies but the low frequencies need something heavy).
posted by unSane at 7:32 PM on January 14, 2011

This may be a dumb suggestion and there's probably a good reason why it cannot be (so don't beat me up anyone), but can't you simply put the computer in a different room, use some long cables to attach a remote screen (which will, of course, be in your recording space) and use a wireless mouse to remotely operate the machine?
posted by MajorDundee at 7:03 AM on January 16, 2011