Voice Isolation

Voice Isolation keeps the voice in a clip and removes what’s around it: background noise and the echo of the room. It uses Apple’s on-device voice model, so nothing leaves your Mac.

Where: Clip tab ▸ Sound ▸ Voice Isolation
Needs: Nothing. The voice model runs on your Mac, with no key and no upload.
Agent tools: set_audio

Isolate a voice

Select a clip with sound, and open the Voice Isolation section of the Sound tab.
Tick Isolate voice. The Amount goes to 80 % and Status reads “Rendering…”.
Keep working. The clip plays without isolation until Status reads “Ready”, then the editor switches over by itself.
Listen, and change Amount if you need to.

Isolation also reduces room echo, so there’s no separate control for reverb. The section reminds you with the line “Also reduces room echo” under Status.

The controls

Control	What it does	Range	Default
Isolate voice	Turns isolation on at 80 %, or off.	On or off	Off
Amount	How much of the isolated voice replaces the clip’s own sound. Quick picks: 50, 80 and 100 %.	0 to 100 %	0 % (off)
Status	What the isolated voice is doing. See What Status says.		Off

Setting Amount above 0 also turns isolation on, and 0 turns it off. Reset in the section’s header does the same as unticking the box.

Choose an amount

Amount blends the isolated voice with the clip’s own sound.

At 80 %, the pauses between words drop by about 14 dB and keep a little of the room, so the voice doesn’t sit in dead silence. This is what the box turns on.
At 100 %, the pauses are silent.
Below that, more of the original sound comes through.

Changing Amount takes effect at once. It doesn’t need the isolated voice to be worked out again.

While it renders

The isolated voice is worked out once for each clip, in the background, when you turn it on. Until it’s ready the clip plays without it, and the editor switches over by itself.

Trimming or slipping the clip works it out again, because the clip then plays a different part of its file.

An export waits for every isolated clip to be ready, and its sheet reads “Preparing” and the file’s name while it does, so a file is never written without isolation. If a clip’s isolated voice can’t be made, the export stops with “Clip 12’s isolated voice could not be rendered:” and the reason.

What Status says

Status	What it means
Off	Isolation is off for this clip.
Rendering…	The isolated voice is being worked out. The clip plays without it for now.
Ready	The clip plays with isolation.
Plays without it at this speed	The clip has a speed change, a ramp or a freeze frame. See below.
Waits for the reversed copy	The clip is reversed, and its reversed copy isn’t ready yet.
Not rendered: and a reason	It failed. “Not rendered: its media cannot be found” means the clip’s file has gone missing, so relink it.
—	Several clips are selected.

Speed, ramps and freeze frames

Isolation plays only at normal speed. A clip with a speed change, a speed ramp or a freeze frame plays without it, and Status says so.

A reversed clip is isolated once its reversed copy is ready.

Good to know

Isolation comes first in the clip’s sound, before the channel choice, the EQ, noise reduction and the compressor. You can use it with Noise Reduction, which then works on the isolated sound. A voice effect is made from the isolated voice too. See How audio works.
Two clips cut from one take are isolated separately, so the sound at the join may differ slightly.
Isolation does nothing on a nest clip, and its Status reads “Off”. Open the nest with ⌘↓ and set it on the clips inside.
With an action selected, Isolate voice and Amount set where the action ends, and the Amount glides across the action, from 0 when the clip’s own Amount is 0. The isolated voice is still made for a clip whose own isolation is off.

With an agent

set_audio sets the amount as isolation, from 0 to 1: 0 is off, 0.8 is what the box turns on, and 1 leaves silence between words. An agent can’t read Status, because the render’s state isn’t in get_project, but an export still waits for it. See Tools: clip sound.