Noise Reduction

Noise Reduction turns down steady background noise such as hiss, hum and fan noise. It works out the noise level from the clip itself, so you don’t need to give it a sample of the noise or a stretch of silence.

Where: Clip tab ▸ Sound ▸ Noise Reduction
Agent tools: set_audio

Remove noise

Select a clip with sound, and open the Noise Reduction section of the Sound tab.
Raise Remove noise while you listen, until the noise is low enough and the voice still sounds natural.

Control	What it does	Range	Default
Remove noise	How much steady background noise to remove. Quick picks: 0, 25, 50, 75 and 100 %.	0 to 100 %	0 % (off)
Depth	Read-only. See The Depth readout.		off

Reset in the section’s header sets Remove noise back to 0.

The Depth readout

Depth tells you the most any part of the sound can be turned down at this setting. It follows Remove noise:

Remove noise	Depth reads
0 %	off
25 %	2 dB at most
50 %	6 dB at most
75 %	12 dB at most
100 %	floor removed

Between those it climbs with the setting, so 90 % reads “20 dB at most”.

Noise Reduction never removes more than the noise level it found, so a higher setting isn’t a stronger cut across the whole sound.

What it can’t do

Noise Reduction isn’t a gate. It works under speech as well as between words, and it doesn’t silence the gaps. To turn the pauses down, use the Gate.

It can’t remove a sound that isn’t steady, such as a door slam or a cough. A long held note may eventually be treated as noise.

To reduce the echo of a room, use Voice Isolation. The two work together: Noise Reduction then works on the isolated sound.

Good to know

It runs after the EQ and hum removal, and before the Gate and the Compressor. See How audio works.
With an action selected, Remove noise sets where the action ends and the amount glides across the action.
Noise Reduction set on a nest clip has no effect. Open the nest with ⌘↓ and set it on the clips inside.

With an agent

set_audio sets the amount as noise_reduction, from 0 to 1. See Tools: clip sound.