Audacity Noise Reduction: Completely Free, Slightly Manual

By the FreeHush crew · Published July 28, 2026 · Last updated July 28, 2026

Free vs paid — wrong question here

There's no paid Audacity and never has been. The real trade is money for effort:

How it holds up

From the manual and the algorithm's design — the honest shape of a spectral-subtraction tool:

Against steady background noise: this is the home game. Because you hand it an exact sample of your noise, it removes precisely that — often more surgically than one-click AI tools, which have to guess. Interview recorded next to a humming fridge? Two minutes in Audacity beats most web tools.

Against variable noise: the profile method assumes the noise at minute one matches the noise at minute ten. Voices, passing cars and keyboard bursts don't cooperate, and pushing the reduction slider harder introduces the classic bubbling, metallic artefacts every Audacity user eventually meets.

What to check on your own file: after processing, listen to the quiet gaps between sentences at high volume — that's where over-reduction announces itself first. If the gaps sound like they're underwater, undo and lower the dB setting.

The two-pass method, step by step

1. Open your recording in Audacity and find a stretch of noise only — a few seconds where nobody speaks.
2. Select that stretch, then run Effect → Noise Removal and Repair → Noise Reduction and click Get Noise Profile.
3. Select the whole track (Ctrl/Cmd+A).
4. Open the effect again; start moderate — Noise Reduction around 10–12 dB — and use Preview.
5. Apply, listen to the between-speech gaps, and re-do with gentler settings if the voice got waterlogged.

When you'll outgrow it

Audacity never expires — but three situations push people onward:

• Live calls are your actual problem — Audacity can't help; that's virtual-mic territory (Krisp, NVIDIA Broadcast).
• Volume — cleaning one file is craft; cleaning every episode is a chore that upload tools (Adobe Enhance, Auphonic) automate away.
• Variable noise keeps beating you — the AI tools' models handle changing noise fundamentally better than a static profile can.

Settings that don't ruin voices

The Noise Reduction dialog has three numbers, and the defaults tempt you to overdo all of them. Starting points that survive real use: noise reduction around 10–12 dB, sensitivity near 6, frequency smoothing at 3. Preview, then adjust one value at a time. If noise still shows through, resist dragging the dB slider to 24 — voices go watery and metallic past ~15 dB. The cleaner trick: run two gentle passes instead of one brutal one (apply at 10 dB, then apply again). Same total reduction, far fewer artifacts.

When Audacity is the wrong tool

Profile-based reduction has one requirement: consistent noise. Fans, hiss, hum — it eats them. What it can't handle is noise that changes: traffic, a café, voices behind you, because the profile it learned stops matching seconds later. For those recordings, upload to Enhance's free tier instead — rebuilds don't care whether the noise held still. And for anything live — meetings, streams — an offline editor is a category error: that's Krisp free for calls or OBS's built-in filter for streams. Audacity's lane is the recording that already exists, and inside that lane it's unbeatable at the price.

Quick questions