How to reduce background noise in Audacity

Audacity is where a huge number of people clean up their first recordings — it's free, it's everywhere, and it has a genuinely capable Noise Reduction effect built in. The catch is that it's easy to overdo, and an over-scrubbed Audacity vocal has a distinctive watery, robotic sound that's worse than the noise was. Here's how to reduce background noise in Audacity properly, step by step.

Key Takeaways

• Audacity's built-in Noise Reduction works in two steps: get a noise profile, then apply it.
• Select a moment of just the noise first — that's what it learns from.
• Keep the reduction gentle; too much gives the watery, underwater artifact.
• Noise reduction is the first cleanup step, before you touch tone or effects.

Audacity has this built in

You don't need a plugin for steady background noise in Audacity — hiss, hum, a fan, room tone. The Noise Reduction effect (under the Effect menu) handles it, and it works the same way as the pro tools: it learns what the noise sounds like from a quiet moment, then subtracts that fingerprint from the whole recording. The trick is entirely in how you feed it and how hard you push it.

Step by step

1. Find a moment of just noise. Select a half-second to a second of the recording where the voice isn't talking — just the background hiss or hum. This is why leaving a beat of silence at the top of a take matters: it's the reference.
2. Get the noise profile. Open Effect > Noise Reduction and click Get Noise Profile. The window closes; Audacity has now learned the noise. Nothing audible happens yet.
3. Select the whole track (or the region you want cleaned).
4. Apply the reduction. Open Effect > Noise Reduction again, and this time adjust the settings and click OK. The three sliders are: Noise reduction (dB) — how much to cut; Sensitivity — how aggressively it decides what's noise; and Frequency smoothing — how it spreads the reduction across frequencies.
5. Preview before committing. Use the preview to check for artifacts before you apply.

Keep it gentle

The single most important thing: use as little reduction as you can get away with. The default reduction is often too strong. Start low — a modest amount of reduction — and only increase it until the noise stops being distracting, not until it's gone. Pushed too hard, Audacity's Noise Reduction produces the tell-tale watery, fluttery, underwater sound as it starts chewing on the voice itself. A little remaining noise under a natural voice always beats silence around a damaged one. (The general principle is in how to remove background noise from vocals.)

Do it first

Noise reduction is the first cleanup step, before any EQ, compression, or effects. If you brighten or compress a noisy recording first, you amplify the hiss and then have to fight it. Clean, then shape. After the noise is down, the next moves are the same as any vocal — fixing the room if it's echoey, then de-essing and tone. The full order is in how to get a clean, clear vocal.

De-essing in Audacity

Audacity's built-in effects are strong on noise but it has no dedicated de-esser. Recent versions support VST3 plugins, so a de-esser like Sibilance loads right in — and its free tier means you can de-ess an Audacity vocal without spending anything, the same way the built-in Noise Reduction costs nothing. Clean noise with Audacity's tool, then de-ess with a plugin, and a free recording chain gets surprisingly far.

The short version

Audacity's built-in Noise Reduction cleans steady background noise well: select a moment of just the noise, click Get Noise Profile, then select the whole track and apply — gently. Start with low reduction and stop when the noise is no longer distracting, before it turns watery. Do it first in the chain, and add a VST3 de-esser like Sibilance's free tier for the esses.

Sibilance is the single-authority de-esser this comes from — a real free tier, and a 7-day Pro trial with no card.

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