Noise Reduction in Audacity: AI Music Cleanup Guide (2026)

First: decide whether this is actually a Noise Reduction problem

You do not have to normalize first

The previous version of this guide treated normalization → click removal → noise reduction as a fixed chain. That is too rigid. Audacity allows normalization before or after Noise Reduction, and the correct order depends on the problem you are solving.

A more useful rule is: repair obvious defects first, reduce genuine background noise only when needed, then make final level and mastering decisions. If your problem is loudness rather than noise, use the Peak vs Loudness Normalization guide.

A safer Noise Reduction workflow in Audacity

What the three main controls actually do

Why 12 dB / 6 / 3 should not be treated as a universal preset

The old article recommended 12 dB Noise Reduction, Sensitivity 6 and Frequency Smoothing 3 as though those values were appropriate for AI music in general. They are not.

Those numbers can be reasonable in some restoration situations, but the correct settings depend on the relationship between the noise and the wanted signal. A quiet hiss beneath a dense instrumental is a very different problem from hiss underneath an exposed vocal intro. A dark synth pad is easier to accidentally classify as noise than a bright percussion-heavy section.

Your target is not a preset. Your target is the smallest audible intervention that solves the actual problem.

Use Residue as your damage detector

This is the most useful part of the workflow for creators who do not want to become audio engineers.

• If the residue sounds mostly like hiss, hum or broadband noise, you are probably targeting the right material.
• If you hear recognizable vocal consonants, hi-hats, cymbals, snare attack or melodic content, reduce the amount or sensitivity.
• If the cleaned version develops chirps, metallic ringing, watery texture or tiny random tones, the noise profile may be poor or the settings may be too aggressive.
• If the noise changes significantly across the song, one global profile may not represent the whole track. Treat separate regions separately—or decide that regeneration/local repair is safer.

Hum and whistles may need a Notch Filter first

A narrow electrical tone is different from broadband hiss. Audacity specifically recommends considering a Notch Filter for mains hum or a high-pitched whistle before applying Noise Reduction.

For North American mains hum, 60 Hz is a common fundamental frequency; in many other regions, 50 Hz is common. Harmonics can also appear above the fundamental. The point is not to blindly notch every multiple—it is to identify the actual tone and remove only what is necessary.

Clicks, crackle, hum or hiss? Use the right first tool

If your main issue is clicks or pops, continue with the updated Clicks & Pops Repair Guide instead of forcing Noise Reduction to solve the wrong problem.

Common mistakes that make AI music sound worse

Where Noise Reduction belongs in the finishing workflow

A practical order is:

Choose the best source → repair clicks/glitches → notch obvious tones if needed → reduce steady noise if needed → tonal/mix work → limiting/mastering → loudness and export checks.

Noise Reduction is conditional. If the render does not have a meaningful noise problem, skip it. Every unnecessary process is another opportunity to damage a track that was already working.

This guide focuses on steady-noise diagnosis and reduction. For transient clicks and pops, use the Click Repair guide; for level targeting, use the normalization guide; for final release preparation, continue to the mastering workflow.