Time Shifting
From Audacity Development Manual
Time Shifting selected tracks to left or right
To shift multiple tracks to left or right, there must be a selection region in all the tracks you want to shift, and you must drag from inside the selection region in one of those tracks.
To select multiple audio tracks for time shift, click in the Track Control Panel of the first track you want to shift, then hold down SHIFT and either:
- click in the Track Control Panel to select the other tracks you want to shift
- use UP or DOWN arrow on the keyboard to select the other adjacent tracks you want to shift.
If a track you don't want to shift is already selected, use UP or DOWN arrow if necessary to move the yellow focus border into it, then ENTER to deselect it.
Having selected multiple tracks for left/right shift, you may still want to drag only one of the selected tracks to fine tune its position. You can do this by temporarily deselecting it as above, or if some of the track lies outside the selection region, drag from outside that region, which moves the track but not the selection region.
If you always want to retain synchronisation between tracks when time shifting, you can alternatively enable Sync-Lock Tracks. When this is enabled, dragging any of the linked audio or note tracks will shift all the tracks in that group (and any labels as well), whether tracks are selected or not.
Time Shifting clips to left or right
An individual clip always shifts when dragged, though if the clip is partially selected, dragging to left or right from outside the selection region moves the clip without moving the region itself. To shift a group of adjacent clips to left or right in a track, leaving other clips alone, use Selection Tool to drag a selection region over the clips you want to shift, then switch to Time Shift Tool and drag from inside that region.
Shifting behind time zero
If an audio track is dragged to the left (earlier on the Timeline) audio data may be hidden before the start of the track. This is indicated by the presence of two arrows at the left edge of the track. Note that audio before the start of the track is not exported unless using Export Multiple with file splits based on tracks.