MIDI Synchronization settings

MIDI Synchronization settings are only available when Show Advanced Tools is selected in Advanced preferences.

You can use these settings to synchronize external slave devices to Logic Pro, which acts as the master.

Figure. MIDI Synchronization settings.
  • Transmit to: Destination 1 checkbox:Activates MIDI Clock transmission.

    Every time you start playback, a Song Position Pointer (SPP) message is also sent. Because not all devices can process SPP, the MIDI system real-time Continue message is also sent. The exception is when you start at position 1 1 1 1. In this situation, the real-time Start message is sent.

    MIDI Clock can easily be sent with other normal MIDI events (notes and controllers, for example). When using multi-port MIDI interfaces (such as the Unitor8), better timing is achieved by sending MIDI Clock to All ports, rather than to several individual ports.

    If MIDI Clock is transmitted to all ports, the events are only sent once from the computer to the interface. If you address individual ports, one event needs to be sent for each port, placing a higher strain on the bandwidth of all ports.

  • Transmit to: Destination 1 pop-up menu:Determines the first discrete MIDI output port for the MIDI Clock signal.

  • Transmit to: Destination 2 checkbox:Activates MIDI Clock transmission.

  • Transmit to: Destination 2 pop-up menu:Determines the second discrete MIDI output port for the MIDI Clock signal.

  • Mode pop-up menu:Determines the MIDI clock transmission mode for synchronized MIDI devices.

  • Start: at position field:Defines the musical position at which the MIDI Clock output should start.

  • “Delay transmission by” field:Use to delay the transmission of MIDI Clock signals. Negative values mean that the MIDI Clock signal is transmitted earlier. This allows you to compensate for any reaction delays in external MIDI Clock slaves.

  • Auto-compensate Plug-in Latency checkbox: Compensates for delays that can be introduced when using plug-ins.

  • Transmit MTC checkbox:Activates the transmission of MIDI timecode.

  • Transmit MTC pop-up menu:Determines the MIDI output port for the MTC signal.

    Note: If you can avoid it, you shouldn’t send MTC to all ports, as it’s very data intensive. If possible, use a MIDI port that isn’t being used for anything else.

  • Transmit MMC checkbox:Allows transmission of MIDI Machine Control. These commands are then sent whenever you operate the transport functions (Start, Stop, Rewind, and so on) of Logic Pro.

    MMC is normally used when Logic Pro is running as a slave to an external master (such as an ADAT), and you want to control the external master’s transport functions from Logic Pro. Logic Pro therefore acts as MMC master and MTC slave simultaneously. If you want to use the external master’s transport controls, you don’t need to use MMC. In this situation, Logic Pro follows the MTC master as a slave. You can also use MMC to record-enable tracks on the MMC slave device.

  • Listen to MMC Input checkbox: Controls Logic Pro by MIDI Machine Control and so-called Full Frame Messages.

    Logic Pro recognizes these commands when listening to MMC Input:

    • Play

    • Deferred Play

    • Stop

    Deferred Play is a special command for mechanically slow synchronization slaves such as reel-based tape recorders. Rather than having the machine play immediately, it is asked to reach the desired SMPTE position before playback is started. There is no noticeable difference in the response of Logic Pro to the Play and Deferred Play commands, as Logic Pro can start playback at any position almost instantly.

    Logic Pro ignores these messages when incoming external MTC (MIDI Time Code) commands are detected.

    Logic Pro also obeys Full Frame Messages, and sets the playhead to a new location, without starting playback. Once again, incoming MTC data has higher priority, if conflicting information is received.

    Some synchronizers send Full Frame Messages (instead of MTC) to locate the slave device (Logic Pro in this case) to a new position, without implicitly starting playback. This is useful when in Slow Shuttle or Single Frame Advance mode with video machines, because the slave device is perfectly located, without being in playback mode.