Remove Background Noise from Audio – Free Noise Reduction Tool

How to Remove Background Noise in Audacity

Step 1: Get Noise Profile

Audacity needs a "noise profile" – a short sample of pure background noise with no speech or music. Find a section in your recording (at least 0.5 seconds long) where only the unwanted noise is audible. Click and drag to select it, then go to Effect > Noise Reduction > Get Noise Profile. Audacity will analyze the noise characteristics and store them for the next step.

Step 2: Apply Noise Reduction

Now select the audio you want to clean. To process the entire track, press Ctrl + A (Windows/Linux) or Cmd + A (Mac). Then open Effect > Noise Reduction and click OK to apply reduction using the profile you just captured.

Step 3: Adjust Settings

Before clicking OK, fine-tune the Noise Reduction, Sensitivity, and Frequency Smoothing sliders to suit your recording. Use the Preview button to hear the effect before committing. If the result sounds unnatural, dial back the Noise Reduction value and try again.

Noise Reduction Settings Explained

Noise Reduction (dB)

Controls how much of the identified noise is attenuated. Higher values remove more noise but can introduce audio artifacts – a warbling, "watery" quality. Values between 6 and 24 dB work well for most recordings. Start low and increase until the noise is no longer distracting.

Sensitivity

Determines how aggressively Audacity classifies parts of the signal as noise. Higher values treat more of the audio as noise to remove. If voices or instruments sound muffled after applying, try lowering this value.

Frequency Smoothing

Smooths the transition between noise-reduced and untouched frequency bands. A value of 3 is a good starting point. Increasing it reduces "musical noise" – the tinny or metallic artifacts that can appear at aggressive reduction settings.

What Types of Noise Can Audacity Remove?

Audacity's Noise Reduction effect works best on stationary noise – backgrounds that stay roughly constant throughout the recording:

• Room hiss / preamp hiss – constant low-level hiss from microphones or audio interfaces
• Fan noise – from computers, air conditioning, or ventilation
• Electrical hum (50/60 Hz) – caused by ground loops or poor cable shielding
• Buzzing – from fluorescent lights or other electrical interference
• Tape hiss – when digitizing old cassette or reel-to-reel recordings

For non-stationary noise such as traffic, crowd chatter, or background music, other tools and techniques will typically be more effective.

Tips for Best Results

• Select a noise sample that is at least 0.5 seconds long and contains no intentional audio.
• Start with moderate settings – try Noise Reduction: 12 dB, Sensitivity: 6, Frequency Smoothing: 3 – and adjust from there.
• Always use Preview before applying to compare processed and original audio side-by-side.
• If audio sounds "watery" or distorted, lower the Noise Reduction value or Sensitivity.
• Record in the quietest environment possible – noise reduction improves recordings but cannot fully substitute for good recording conditions.

Alternative Noise Reduction Techniques

When the standard Noise Reduction effect is not enough, Audacity offers additional tools:

• Noise Gate – Silences audio that falls below a set volume threshold, useful for eliminating noise between speech or musical phrases. Found under Effect > Gate.
• Spectral Editing – Switch to Spectrogram view to visually identify and surgically remove specific noise frequencies. Right-click a track header and select Spectrogram.
• Equalization – Use the Filter Curve EQ to cut the frequency range where noise is most prominent without affecting the rest of the audio.
• MuseHub plugins – The MuseHub platform offers additional noise reduction and audio restoration plug-ins that integrate directly with Audacity.

Download Audacity Free

Ready to clean up your recordings? Download Audacity for free on Windows, macOS, or Linux and start removing background noise today.