Revert to Backup ⌃⌥⌘B

Make a backup before doing any audio file editing.

This command cannot be undone. Replace the current audio file with the backup file (if it exists).

Backup audio files in the Audio File Editor in Logic Pro — Apple Support

Although the Undo History and standard Undo functions are available in Logic Pro, try to get in the habit of creating backups before processing or editing. This provides a safety copy of your audio recordings in case something unexpected happens, due to a processing error or other unforeseen event.

  Selection -> Region ⇟

Redefines the length of the region.

Select audio in the Audio File Editor in Logic Pro — Apple Support

Define the selected area using a region

In Logic Pro, select a region in the Browser or main window, then choose Edit > Region → Selection.

This function is useful if you want to reselect the entire region for cycled playback—after performing a number of edits, for example.

The reverse can also be done, allowing you to redefine the length of an existing region by choosing Edit > Selection → Region.

You can modify selections by changing their start or end point, or you can move the entire selected area completely.

Note: If you choose Edit > Snap Edits to Zero Crossings, any length adjustments to audio region start or end points snap to the nearest zero-crossing point of the waveform.

  Fade In ⌃I

Add a fade in to an audio file. This is a destructive operation.

Add fades to audio files in Logic Pro — Apple Support

Fade In: Volume is set to 0 at the start point of the selected area, and the fade in occurs over the length of the selection.

  Create Backup ⌃B

Create a backup copy of the current audio file. The Audio File Editor performs destructive edits which cannot be “undone”. Reverting to the backup copy is the only way to undo the edits.

The Project Audio Browser has a command — Backup File(s) — which uses the same keyboard mapping. Files backed up have the same ‘.dup’ extension as they do when backed up in the Audio File Editor.

Backup audio files in the Audio File Editor in Logic Pro — Apple Support

In Logic Pro, choose Audio File > Create Backup from the Audio File Editor menu bar (or press Control-B).
A copy of the audio file (with the extension .dup) is created in the same folder as the source file.

The Project Audio Browser in Logic Pro — Apple Support

The Project Audio Browser shows all audio files and regions that have been added to or recorded in your project, whether or not they are used in the Tracks area. Regions shown in the Project Audio Browser that are not used in the Tracks area are indicated in red.