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Audacity: Removing Background Noise
Audacity, Version: 3.1.3. Be aware that different versions of Audacity will vary in appearance and functionality.
Always record in the quietest setting possible. Even quiet rooms produce sound, however, such as from electronic devices and air ducts; this sound is called room tone, which is captured in recordings as unwanted background noise. Some background noise can be removed during editing, such as consistent room tone. Be aware that random noises, such as dogs barking in the background, are more difficult to remove.
Capture at least 10 seconds of room tone during recording sessions, which will be used to remove background noise in editing. To capture room tone properly, record the “silence” of the room without any additional sounds such as shuffling or movement.
Be aware that the Noise Reduction effect can cause distortion. Use with caution.
To remove unwanted background noise:
- Open an audio track that contains room tone. If a clip for room tone was not recorded, use a recording that has a few seconds of silence in it.
- With the Selection Tool, click-and-drag to highlight a section with a few seconds of silence.
- Navigate to Effect > Noise Reduction. A new window will appear.
- Under “Step 1,” click the “Get Noise Profile” button. The window will close and Audacity will sample the highlighted section for the noise profile.
- Select the desired clip for noise reduction.
- For a single clip, click the top of the clip (near the clip name).
- For multiple clips, click-and-drag to highlight all clips.
- Noise Reduction (db): Controls the volume reduction to be applied to the noise profile. Use the lowest value that reduces the noise to an acceptable level. Start with 12db.
- Sensitivity: Controls how much of the noise profile will be considered unwanted noise. Be careful with this setting. Sensitivity that is too high or low will cause distortion. Start with 6.00.
- Frequency Smoothing (bands): Blends frequencies together. Start with 3 and keep as low as possible.
- Reduce and Residue: select Reduce to filter out noise. Use Residue to hear the exact noise that will be filtered out when previewing.
Listen to the track to determine if the effect worked properly. If there is still a lot of background noise, or if the audio now sounds strange, undo the effect (Edit > Undo), and adjust the settings in Step 2 of the Noise Reduction Effect. If problems persist, try again from the beginning and utilize a different noise profile.
- Audacity: Information
- Audacity: Downloading & Installing
- Audacity: Interface Overview & Tools
- Audacity: Recording Audio
- Audacity: The Timeline & Tracks
- Audacity: Importing Audio Files
- Audacity: Editing Audio
- Audacity: Increasing Clip Volume (Amplify)
- Audacity: Fixing Inconsistent Volume (Compressor)
- Audacity: Fading & Adjust Volume in Specific Sections (Keyframing)
- Audacity: Splitting & Panning Tracks
- Audacity: Removing Background Noise
- Audacity: Saving & Sharing Projects
- Audacity: Exporting an Audio File (MP3, WAV, etc)