How to Remove Background Noise in Audacity: Step by Step

To remove background noise in Audacity, use its Noise Reduction effect. You select a short stretch of the recording that has only the noise, tell Audacity to learn that noise, then select the whole track and apply the effect. It works best on steady noise like hiss or a fan. If the recording is a vocal, the Vocal Noise Remover is a second option that gives you the clean vocal and the noise on separate files.

What kind of noise Audacity can remove

Noise Reduction works by learning what the noise looks like, then turning down that sound everywhere in the recording. That makes it good at noise that stays the same.

• Hiss from a cheap microphone or a quiet preamp.
• Hum from electrical gear.
• A fan or an air conditioner running in the background.
• Computer noise like a laptop cooling fan.

It is much weaker on noise that changes: a barking dog, a siren, people talking in the next room, a car going past. The effect cannot learn a sound that never repeats the same way.

Before you record: get a noise sample

The method needs a clean sample of just the noise. So when you record, stay silent for a few seconds at the start. Do not talk, breathe loudly or move. Leave the fan or the hum running, because that is the noise you want Audacity to learn.

Two to five seconds is enough for most recordings. If you already finished the take with no gap, look for any pause between words where nothing but noise is playing. Even half a second can work.

Step by step in Audacity

1. Open your recording. Drag the file into Audacity or open it from the File menu.
2. Select only the noise. Click and drag over the quiet stretch where there is no voice, just the background sound. Zoom in if you need to see it clearly.
3. Open the Noise Reduction effect. You will find it in the Effect menu.
4. Get the noise profile. In the Noise Reduction window, press the button that gets the noise profile. This tells Audacity what the noise sounds like. The window closes by itself.
5. Select the whole recording. Press Ctrl+A on Windows or Cmd+A on a Mac.
6. Open Noise Reduction again and apply it. Now the effect knows the noise. Press OK to apply it to the selected audio.
7. Listen. Play the result with headphones. If the noise is still there, undo and try again with different settings.

The exact look of the window can change a little between Audacity versions, but the two steps stay the same: learn the noise, then apply.

The settings in the Noise Reduction window

The window has three sliders. A few plain words about what they do.

• Noise reduction (dB). How much the noise is turned down. A bigger number removes more noise and can damage the voice.
• Sensitivity. How strict Audacity is about what counts as noise.
• Frequency smoothing. How much the effect blends neighboring pitches. More smoothing sounds less like bubbles and chirps, but can leave a bit more noise.

Start with the default values. If the noise is still too loud, raise the reduction a little. Do not push it far, because strong settings give a watery, robotic sound. A small, clean cut usually sounds better than a big, damaged one.

Why it sometimes sounds worse

Noise reduction always makes a trade. The effect turns down every sound that looks like the noise, and parts of a voice can look like noise too. Breaths and soft consonants such as "s" and "f" are the usual victims.

Signs you went too far:

• The voice sounds thin or underwater.
• There are odd tinkling or bubbling sounds, often called artifacts.
• The ends of words get cut off.

Undo and use a lower reduction number. If the noise is changing and not steady, accept a bit of it, or re-record in a quieter spot.

When the recording is a vocal

If you have a vocal take, an acapella or a voice-over with noise in it, there is a second way. The Vocal Noise Remover is built only for voices. It is not a noise tool for any kind of audio.

Here is how it goes:

1. Upload the vocal. MP3, WAV, M4A or FLAC, up to 10 minutes. You sign in with Google the first time.
2. Press the orange key. It reads "Remove the noise" and shows the price first. Each minute costs 1 credit, and new accounts start with 5 free credits.
3. Wait a minute or two. Most files take 1 to 3 minutes.
4. Listen to the two files. You get "Clean vocal" and "Noise only". Each downloads as a 320 kbps MP3.

Unlike Audacity, you do not need to find a stretch of pure noise first. And the "Noise only" file lets you check what was taken away. If pieces of the voice are in it, the tool took too much.

Both methods can leave a trace, especially on loud or changing noise. Use whichever suits the take. Some people run Audacity first for hiss, then clean the rest.

If the problem is room echo rather than noise, neither tool is the right one. Use the Reverb Remover instead. If the voice is inside a finished song, take it out first with the Acapella Extractor.

Tips to avoid noise next time

• Record in the quietest room you have, and turn off fans and air conditioners.
• Keep the microphone close to your mouth.
• Lower the input gain so the mic does not boost the hiss.
• Always record a few seconds of silence first. It is the noise sample you need later.

FAQ

Does Audacity remove background noise from any recording?

It works on many recordings, best on steady noise like hiss, hum and fans. It cannot fully remove noise that keeps changing, like traffic or a barking dog.

Why does my voice sound robotic after noise reduction?

The effect was set too strong. Undo it and try a smaller reduction value. A little leftover noise sounds better than a damaged voice.

Do I have to select a noise sample first?

Yes. Noise Reduction needs a stretch of audio with only the noise so it can learn what to remove. If you have none, look for a short pause between words.

Is the Vocal Noise Remover the same as Audacity's Noise Reduction?

No. It is a separate tool, and it only works on vocals. It gives you a "Clean vocal" file and a "Noise only" file for 1 credit per minute, and new accounts get 5 free credits.

Can I remove noise from a whole song?

Not with this method. Noise reduction is meant for voices and spoken recordings. A song has music in it, and the effect may treat parts of the music as noise.