Pro Tools channel pairs can be routed to multiple physical outputs on an audio interface through the Hardware Setup.
For example, if you assign Channels 1–2 to both outputs
Analog 1–2 and
Analog 3–4, when you send a signal to Pro Tools Channels 1–2, that signal will be routed simultaneously to both pairs of output ports on your audio interface.
This lets you send the same signal (such as a stereo pair, a stem mix, or a multichannel mix) to multiple destinations (such as multiple mastering devices).
The output name updates with a plus sign (“+”) before it to indicate that multiple output ports are selected. In the pop-up menu, each physical port pair assigned to that Pro Tools output pair is indicated by a check mark.
Pro Tools output pairs can also be routed to multiple audio interface outputs in the I/O Setup. For more information, see
Configuring Hardware in I/O Setup.