Internal Sync Metro can function as the master, providing the timing source. In order to designate Metro as the master, you need to set the Sync setting pop-up menu in the Transport window to Internal Sync. Internal Sync synchronizes MIDI data to the Macintosh’s internal clock; it does not sync data to SMPTE. As the master, Metro generates all timing messages; start, stop, continue, MIDI clock, and song position pointer messages are sent through the MIDI outputs to control external devices.