When Show Advanced Tools is selected in the Advanced preferences pane, you can create and edit Track Stacks. If Show Advanced Tools is unselected, existing Track Stacks in a project will play back, but you can’t create new ones or edit existing ones.
You create a Track Stack by selecting (adjacent or nonadjacent) tracks in the Tracks area. Nonadjacent tracks move so that all tracks are grouped together in the Track Stack. Both types of Track Stacks can contain any combination of track types as subtracks. A folder stack can also include summing stacks as subtracks.
You can hide the subtracks of a Track Stack to save space in the Tracks area, or show them in order to record or edit. You can add or remove tracks from a Track Stack, and reorder tracks in a Track Stack (reordering tracks doesn’t affect the sound).
After creating the summing stack, you can route individual subtracks to a different destination. If you do so, however, the rerouted subtracks are no longer controlled by the main track’s channel strip.
Select the tracks you want to include in the Track Stack. The selected tracks can be adjacent or nonadjacent.
Do one of the following:
Choose Track > Create Track Stack.
Control-click the header of one of the selected tracks, then choose Create Track Stack from the shortcut menu.
In the Track Stack dialog, do one of the following:
To create a folder stack: Select Folder Stack, then click OK.
To create a summing stack: Select Summing Stack, then click OK.
Click the disclosure triangle to the left of the track icon in the main track.
To show or hide the subtracks for all track stacks in a project, Option-click the disclosure triangle for any track stack in the project.
Drag the header of the track you want to add between two of the subtracks in the Track Stack.
Note: When you add a track to a summing stack, its routing changes to the aux assigned to the main track.
Drag a subtrack by its header up or down inside the Track Stack.
Drag the subtrack outside of the Track Stack (below the last subtrack, or above the main track).
When you remove a subtrack from a summing stack, the track’s output routing changes from the aux used by the main track to the main outputs.
You can flatten a Track Stack, in which case the subtracks again become normal tracks.
When you flatten a folder stack, the main track is deleted if its volume fader is set at 0 dB (unity gain) and it contains no automation data.
When you flatten a summing stack, the audio subgrouping is retained, unless there is no audio processing on the main track aux (no plug-ins, volume fader set at 0 dB, Pan/Balance set to neutral, and no automation data). In this case, all subtracks (or their audio subgroups) are routed to the Stereo (or Surround) Main output, and the main track Aux is deleted.
Do one of the following:
Select either the main track or a subtrack, then choose Track > Flatten Track Stack from the Tracks area menu bar.
Control-click the track header of the main track or a subtrack, then choose Flatten Track Stack from the shortcut menu.