Mixing : Basic Mixing : Audio Input and Output Paths : Multiple Output Assignments

Multiple Output Assignments
Pro Tools audio, Auxiliary Input, and Instrument tracks can be assigned to multiple output paths. Assigning to multiple paths is an efficient way to route an identical mix to other discrete outputs, for simultaneous monitor feeds, headphone mixes, or other situations where a parallel mix is needed.
To assign a track to multiple outputs:
1 Assign a main output path by selecting it from the track’s Output Path selector.
2 Start-click (Windows) or Control-click (Mac) an additional output path in the track’s Output Path selector. The newly selected output destination is added as an additional output.
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Option-Control-click (Mac) or Alt-Start-click (Windows) to add the assignment to all tracks, or Option-Shift-Control-click (Mac) or Alt-Shift-Start-click (Windows) to add to all selected tracks.