Background noise can be a frustrating artifact on an otherwise good recording. Sometimes you also just have a recording that you can’t reproduce, so you want to do whatever you can to remove that background noise like in the case of audio captured as part of a video. Relatively straightforward tools like EQ can only do so much, which is why more modern tools exist which are able to differentiate between the noise and the desired audio to effectively clean it up. Most of these tools are behind a paywall, so let’s talk how to remove background noise in Audacity, one of the best freeware DAWs available today.
How to Remove Background Noise in Audacity
Removing background noise in Audacity to clean up your audio is a relatively straightforward process, so let’s take it step by step.
Step 1 – Import Your Audio Into Audacity
First thing’s first; you need to drag and drop the audio clip you want to remove background noise for right into Audacity.
Note that in the case of a video, you can’t drag and drop that video file into Audacity to get its audio that way. Instead you need to isolate its audio which you can easily do via any video editing software or plenty of free tools online which are a search away.
Regardless, once you have your audio drag and dropped into Audacity, you’ll see it populate the track, showing the dynamic waveform of that clip.
Step 2 – Select an Isolated Segment of Noise and “Get Noise Profile”
Now it’s time to teach/train Audacity on the type of noise we want to remove.
To remove background noise in Audacity, we’re going to be using their aptly named “Noise Reduction” effect from the “Effects” tab at the top of the screen.
To teach Audacity what we want to get rid of, we simply need to highlight a small segment of our audio which represents said noise.
The longer the stretch the better; in my example I have a roughly 10 minute clip of dialogue which was recorded outside so you have a decent amount ambient wind on microphone noise. There are plenty of 3-5 second stretches of purely noise, i.e. no speech which all work well.
I simply highlighted a couple seconds of that noise, selected “Noise Reduction” from the “Effects” tab at the top of the screen, and clicked “Get Noise Profile:
Don’t worry about the rest of the settings yet; the popup will disappear as Audacity quickly construct a noise profile to target that specific type of audio and attenuate it based on the settings you choose in the next step.
Step 3 – Adjust Your Settings, Preview to Taste, and Run
Now bring the “Noise Reduction” effect up once again by selecting it again in the “Effects” tab.
You’ll see the following options:
Noise Reduction
The noise reduction setting is self-explanatory, this is the degree it will bring down the targeted audio which, as you can see, this is measured in decibels.
Sensitivity
The sensitivity determines how aggressively it targets the noise. The higher you turn this, the greater chance that the audio you want included will be affected, as well.
Frequency Smoothing
This is for removing additional artifacts when maximum sensitivity setting isn’t getting it done.
The best settings in how to remove background noise in Audacity will vary from track to track with the noise itself.
This is why the “Preview” button exists; it allows you to hear the effects of your settings before you apply them, allowing us to continue to tweak the settings, preview, and repeat until we find the perfect balance.
You should select a stretch which contains the audio you want to clean up for this preview section. In my case it’s just a 3 second span of the speech with the noise on top of it.
You’ll find that if you are too aggressive with the settings, the audio will begin to hollow and thin out. If that happens, dial back the “Sensitivity” and try it again.
Once you’re satisfied with the results, you can double click anywhere on the audio clip to select the entire thing. Bring back up the “Noise Reduction” effect and click “Ok” (it will have saved your settings from last time).
Note that this may take a few seconds depending on the length of the audio you’re affecting.
You can also use the “Repeat Effect” command to run those settings again in the “Effects” tab, or just type the shortcut Ctrl-R in Windows to run it again, though this might cut more than you want.
Step 4 (Optional) – Repeat On Other Types of Noise
You may have more than one type of noise affecting your audio.
Once it’s finished attenuating the first type of noise, you can repeat the process for a second type of noise, isolating that and re-training Audacity to create a profile for that.
That’s how to remove background noise in Audacity.
If this method isn’t getting it done, you might try enlisting the help of a premium option.
When it comes to isolating speech from any kind of background noise, meaning when music isn’t a factor, I can’t say enough good things about Waves’ Clarity Vx Pro which uses a very sophisticated model to strip all background noise from speech/vocals/narration – any kind of voice related audio which is covered by background noise.
Besides how effective it is, it’s nice that it’s as simple as turning a dial to cleanly isolate OR REMOVE the voice altogether.
Admittedly that’s a much bigger investment rather than Audacity which is free, but it works within Audacity like any other plugin and has saved audio from my videos not to mention audio from countless clients of mine time and time again.
Still, with the right settings, you’ll be very impressed at the results you can achieve through Audacity’s stock “Noise Removal” to clean up your audio, it just takes a little fine tuning like I outlined using the steps which I went over above. Happy cleaning!
