Undo, redo, A/B switch

The Undo and Redo buttons at the top of the FabFilter Pro-Q 4 interface enable you to easily undo changes you made to the plug-in. With the A/B feature, you can quickly switch between two different states of the plug-in.

• The Undo button at the left will undo the last change. Every change to the plug-in (such as dragging a knob or selecting a new preset) creates a new state in the undo history. The Undo button steps back through the history to restore the previous states of the plug-in.

• The Redo button cancels the last undo command. It steps forward through the history until you are back at the most recent plug-in state.

• The A/B button switches from A to B and back. Before switching, the current state of the plug-in is saved, so if you click this button twice, you are back at the first state. The button highlights the currently selected state (A or B). In the example above, the A state is active.
• The Copy button copies the active state to the inactive state. This marks the current state of the plug-in and allows you to go back to it easily with the A/B button. After clicking Copy, the button disables itself to show that both states are equal, so there is nothing to copy anymore.

Notes

• If the plug-in parameters are changed without using the plug-in interface, for example with MIDI or automation, no new undo states are recorded.
• The Undo and Redo buttons will disable themselves if there is nothing to undo or redo.

Next: Loading presets

See Also
Overview