Noise reduction is one of the few places in audio where doing the right things in the wrong order actively damages the result. Every clean-up stage analyses the signal it receives, so each process you run changes what the next process can see. Run broadband noise reduction before removing clicks, and the denoiser learns the clicks as part of the noise profile, smears them, and makes them harder to remove forever.
The principle underneath the whole sequence: remove the most distinct, most localised problems first, and the most diffuse problems last.
Here’s the order, and the ‘why’ behind each noise reduction.
0. Fix it at the source
Before any plugin: can you re-record, swap a cable, kill the fridge, move the mic? Every minute spent here saves ten more further downstream, and the result is better than any restoration. Get it right at the source. Only when the recording is what it is do you move to noise reduction processing.
1. Clicks, pops and crackle first
These are the most localised events in the file – microseconds long, totally distinct from the programme material. Removed first, they’re clean excisions. Removed later, after other processing has smeared their energy across time and frequency, they stop being discrete events and become baked-in artefacts. Surgical problems get surgery first.
2. Hum and tonal noise second
Mains hum and its harmonics are statistically predictable – fixed frequencies and steady in level. That predictability is exactly what makes them easy to notch out precisely now, and exactly what gets destroyed if a broadband denoiser processes them first, turning clean tonal spikes into wandering residue. Remove the predictable noise while it’s still predictable.
3. Broadband noise third
Hiss, room tone, preamp noise — diffuse, spread across the whole spectrum. The denoiser needs the cleanest possible picture of “what is noise” to work transparently, which is why everything distinct had to leave first. Feed it a signal still carrying clicks and hum and you’ve polluted its noise profile; the result is the watery, artefact-heavy sound where everyone blames it on the plugin. The plugin was fine. It’s the order that wasn’t.
Run it gently, possibly in several light passes – rather than one aggressive one. Over-doing noise reduction often sounds worse than the noise did. Every process becomes a cost/benefit analysis. What is noise reduction processing really costing you in pure magic from your audio? Granted, some audio is downright awful, but for other line-call decisions, you must consider if the cure is better than the disease.
4. Reverb and ambience last
De-reverb is the most invasive, heaviest process of the lot, as it’s making probabilistic guesses about what’s a direct sound and what’s a reflection. It needs every other contaminant gone to guess well, and even then, restraint wins. A little honest room beats the underwater sound of over-processed de-verb noise reduction.
The judgement layer
The sequence tells you the order. It doesn’t tell you how far to go – that’s a decision made in context, like everything in mixing. A noise floor that’s a problem in a sparse acoustic ballad is completely masked in a dense rock chorus. Perfectionist clean-up work, that strips the life out of a performance, is a worse outcome than mild noise nobody would ever notice. Clean enough to disappear, not clean enough to impress a spectrogram. Check out the noise left on MAGIC!’s “Rude” hit from 2013. The first few seconds before the song start and the dead air after the last hi-hat closes are the biggest tell: It is bathed in (presumably) tape hiss – and loads of it!
But, it doesn’t matter, because the song shines through in spite of it.
Knowing how much noise reduction is required – not just how to apply it – is the kind of judgment call the Level Up Pro Mixing System trains you to make with confidence.
The Mix Artistry free tools page lets you reference the correct chain without memorising it.
Mix Artistry – learn to mix commercial-quality music by understanding the why, and how to get there with a reliable system – every time. Free tools + the Level Up Pro Mixing System at https://www.mixartistry.com. Get it right at the source.
