Background noise is a constant frustration when it comes to trying to record anything via a microphone. There are many things you can do to mitigate or attenuate the background noise, so let’s talk how to remove background noise from a mic.
How to Remove Background Noise From a Mic
Let’s cover 4 different effective things you can do for how to remove background noise from a mic to get cleaner audio, beginning with the obvious.
Remove As Much Noise as Possible
I said we’d be starting with the obvious. The first thing to do is identify what is causing the noise and try to remove or dampen as much of it as possible.
This could include turning off the air conditioner or any fans in the room or covering vents, at least while you record.
It could mean recording at night when there’s less noise coming from outside, as well.
This can even mean dampening as much of those sources of noise as possible, like putting a blanket over your computer if that’s the main cause of noise itself.
I’m not advocating that you keep your computer’s fans covered with no outlet as a general rule, only in the very limited time when you’re recording with the microphone.
Point Microphone Away From Source of Noise
Most microphones we record with are cardoid in polar pattern, meaning that they capture what’s directly in front of them while largely ignoring noise to the sides and behind it.
Take advantage of this “dead zone” of your microphone by pointing it away from the most offending sources of noise.
For instance, if your computer fan is a problem, set up the microphone so that it’s least responsive spot of the back is what’s facing the computer. In other words, you’re facing your computer with the microphone between you and the computer with it facing you.
Create a Sound Proof Box
With a few squares of sound dampening foam and an average sized cardboard box, you can easily and cheaply fashion a little sound proof box for your microphone to seriously remove background noise from a microphone.
I’ve done this myself – simply get a 12x12x12 cardboard box, cut a hole in the bottom for the microphone/stand to feed through, and you’ve got a miniature vocal booth.
It’s not a perfect solution, but it filters out the majority of the room’s noise as you record.
An added bonus is that this cuts down on room reflections getting on the recording so you get the driest audio possible.
Turn Down Gain on Microphone and Recording Hardware
Many microphones feature a gain-notcher so you can remove 10dB for example from the input level on the microphone itself. Some microphones even have an onboard gain dial so you can adjust the input level.
You can do the same thing on your audio interface.
While the onboard feature is typically for when you’re hitting that microphone with a loud signal, the point here is keeping the input gain level low ensures that you only really pick up whatever it is that you’re recording.
A good rule of thumb is to follow my gain staging cheat sheet, ensuring that the average level of what you’re recording is roughly -18dB with peaks at around -12 to -10dB AT MOST.
This yields much cleaner audio on the in, not to mention it delivers better level for mixing purposes which yields better results from the plugins you use to process that audio.
Responsible gain staging also creates naturally louder mixes and masters with less gain reduction necessary from limiting (a good thing).
Fix It in Post
Lastly, if you do happen to pick up some background noise on your microphone, you can easily clean it up in post.
An easy way to remove background noise from a microphone after the fact is to insert a gate early on in the processing chain.
Set the gate’s threshold to just below the quietest practical audio you want on the track, so the quietest instance of the vocal performance, guitar recording, etc.
This gives you a pristine, completely noise free recording which you can then process with EQ, compression, etc. as normal. Check out my overview on how to use a gate for more information.
Lastly, and one final tip, remember to record (and mix) at 24 bit depth as this points a lot more distance between the point of clipping and the noise floor. Refer to my overview on the noise floor for more information on how you can mitigate its effects to achieve cleaner, quieter recordings.
