How to Remove Background Noise in Audacity (3 Steps)
Background noise can be a real downer - especially when your air conditioner or neighbors lawnmower gets picked up by your mic and ruins an otherwise perfect recording.
Audacity is a free, open-source audio editing software that makes it simple to remove unwanted background noise. The platform has a short learning curve, and most podcasters find it fun and easy to use.
In this tutorial, we'll show you how to use Audacity to remove distracting recording sounds while keeping your original audio intact.
Download: Audacity (Compatible with Mac, Linux, & Windows)
How to prevent background noise
Audacity makes removing noise pretty straightforward, but it's still an extra step that adds additional time to your podcast workflow. These tips help prevent the need for noise reduction and reduce your time spent editing.
Optimize your recording space
Where you record your podcast is the single most crucial factor in your audio quality. To improve your home podcasting space, we suggest finding a quiet, small room away from HVAC units, traffic, external hard drives, white noise, fans, etc. You can also improve your room tone by choosing a space with natural sound absorbers like curtains, rugs, carpet, couches, etc.
Use a dynamic mic
There are two main types of podcasting mics: condenser or dynamic. Condenser mics are much more sensitive devices designed to capture ambient room noise, while dynamic mics have a more focused range of frequencies, causing it to pick up less ambient sounds. The Samson Q2U is our top pick for an affordable, quality, dynamic mic with USB and XLR hookups.
Turn down the gain & get close
Turn down the gain (the mic's sensitivity) and get closer to it. Speaking directly into the mic won't distort your audio as long as you lower the gain, and it will help ensure your mic focuses on picking up the frequency of your voice.
Pro tip: Adjust the gain of your recorder (or DAW) so your voice peaks around -12 and -10db.
Minimize computer fan noise
Computers can make a significant amount of noise when they get hot. You can turn your mic away from the computer to help mitigate this effect and reduce the amount of software running to prevent the fan from turning on.
Even if you follow all these tips, sometimes unwanted recording sounds still find their way into your episode. Thankfully, modern software makes this issue fairly easy to correct.
Remove background noise in Audacity (3 steps)
If you haven't already, download Audacity and go to File > Import > Audio to select the track you want to edit. In our audio file, the mic picked up a hum from the computer fan (one of many ways unwanted sound can sneak in.)
Now that you've imported your track into Audacity's workspace, you can follow these three steps to isolate your background noise and minimize it throughout the entire recording.
#1 Get a noise sample
The first thing you'll do is help Audacity isolate the background noise you want to remove. In this example, we're isolating some unwanted fan noise from the audio recording and letting Audacity know the frequency we want to remove. Make sure you have a recorded selected where there's no one talking, and it's just background noise.
If you don't have a selection this big, find somewhere in the audio you can isolate. The important thing is to isolate a section with only the background noise, so it doesn't ruin your voiceovers, dialog, music, etc. Now, click and drag your selection with the Selection tool.
#2 Apply noise reduction
Once you isolate your clip, go to Effect > Noise Reduction. Select Get Noise Profile to let Audacity know which frequencies to filter out and which to ignore.
Now that you told Audacity what particular frequencies you want to remove, select the entire track, so Audacity removes it from the whole recording.
Go back to Effect and select Noise Reduction again to remove the background noise frequency anywhere it appears in your audio file.
#3 Tweak the settings
The first option you have is the amount of noise reduction that you want Audacity to take out. You don't want to overdo it because it might make your audio sound like you're recording underwater. As a general guideline, 12 decibels is a good place to start.
Next, you'll have the option to adjust sensitivity and frequency-smoothing bands. We suggest leaving these on their default settings of six and three.
There are a couple more levers to pull from to isolate the noise frequency even more, but we suggest starting with the default settings. If you get too in the weeds adjusting these levels, you might end up with worse problems than the original background noise.
From here, you can preview how your audio sounds with these settings applied. If you still hear your background noise, you can increase the noise reduction by going to 13, 14, 15, 20, 30 decibels — whatever you think is appropriate.
When you find the right level, click OK. You can see here that Audacity removed most of the noise, but there's still a little bit left.
To remove the remaining noise, hit Command +Z (or Ctrl + Z), and go back to Effect > Noise Reduction. Here, you can increase the reduction to 15 instead of 12 and hit OK.
Now, recheck the audio to see how it sounds. You might have to repeat that step a few times to get an acceptable result. That's all there is to it!
Additional thoughts & resources
As you can see, noise removal is a give and take, but the trick is to apply just enough reduction to remove the background noise without negatively impacting the rest of your audio.
Audacity is an excellent audio editing tool, widely used by digital audio creators. These tutorials can help you get more comfortable using the platform to edit your own podcast!
- How to Edit a Podcast in Audacity — YouTube
- How to Use the Compressor in Audacity — YouTube
- How to Normalize Audio in Audacity — YouTube
- How to Move Audio in Audacity — YouTube
- How to Export Audacity Files as MP3 — YouTube
- How to Cut a Track in Audacity — YouTube
- How to Fade in and Fade Out in Audacity — YouTube