Mastering

Revisions and A/B testing

Every change is a new revision and nothing is lost; switching keeps the song playing. How the A/B list works, how to star a favourite, and the shortcuts.

Updated Sep 3, 2026
Click between revisions while the track plays, flip Mastering OFF to hear the original, star the keeper.

#What a revision is

A revision is one render of your 30-second section with one set of settings: engineer, intensity, the eleven Revision Suite options, and the Custom EQ curve. The first one is made for you and called Default Revision. Every prompt, reference, engineer change or Save Changes adds another. Prompt revisions are named after the prompt; manual ones are "Revision 2", "Revision 3" and so on.

#The Mastering A/B list

One row per revision, one column per option. The header icons name the columns; hover them for the label.

The list at the bottom of the workspace is the heart of the workflow. Each row is a revision, and the columns show the value of every option, so you can see at a glance what differs between two masters without opening anything. A row that is still rendering shows a spinner; a failed one says so.

  • Click a row to switch to that revision. Playback keeps its position, so you hear the same bar with different settings. The Revision Suite and the EQ faders update to match.
  • Star a row to mark it as your favourite. The star is a note to yourself and to anyone you share the session with; it does not change what finalize renders.
  • Hover a name to read the full prompt behind a truncated title, and use the small copy icon next to it to copy that revision's mastering seed.

#Mastering ON / OFF

The single most useful button in the room.

The switch under the waveform flips between the selected revision and your untouched original at the same playback position. Use it constantly. A master that only sounds better because it is louder will give itself away when you match the levels in your head; the difference you want to hear is depth, clarity and control, not volume.

#Full preview

The Full chip renders the whole song with the selected revision's settings.

The Full chip next to the waveform renders the entire track with the selected revision, so you can check the quiet verse and the last chorus before committing. It takes longer than the 30-second preview and it is a Plus feature. The finalized master is rendered separately at full quality; the full preview is an MP3 for listening.

#Keyboard shortcuts

KeysAction
SpacePlay or pause
Previous revision
Next revision
Seek back 5 seconds
Seek forward 5 seconds
EnterSend the prompt (when the prompt field is focused)
Shift+EnterNew line in the prompt
EscClose the engine popover or cancel an inline rename

#Revision limits

Revisions are free to make, with a per-project cap: 10 on a free account, 20 on Unlimited, and no cap on Unlimited Plus. Hitting the cap opens a nudge to Plus; it never deletes anything. If you are close to the limit, delete the experiments you know you will not use from the row menu, or finalize what you have and continue later.

Which revision does Finalize use?

The one that is selected (highlighted) when you press Finalize, not the starred one. Click the row you want first.

Can I rename a revision?

Not the revision, but you can rename the project from the Track Name field at the top right (pencil icon, Enter to save).

I switched revisions and the EQ faders moved on their own

That is the EQ recalling that revision's curve. Each revision keeps its own six-band curve.

Ready to hear it on your track?

Upload a mix, get the first master in about a minute, and keep the revisions you like.

Try it on your own track

The first master takes about a minute. Previews are free.

Open Mastering