MIDI Synchronization settings in Logic Pro

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

You can use these settings to synchronize external devices that receive MIDI clock from Logic Pro. You can configure MIDI clock synchronization settings independently for up to 10 external devices.

Destination pop-up menu: Sets the MIDI output port that receives MIDI clock signal. Select “All” to use the same configuration for every MIDI output port.
Clock checkbox: Activates MIDI clock transmission for the MIDI output port shown in the Destination field of that row.
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.
Delay [ms] field: Use to delay the transmission of MIDI clock signals for the MIDI output port of that row. Negative values mean that the MIDI clock signal is transmitted earlier. This allows you to compensate for any reaction delays in external devices receiving MIDI clock.
PDC checkbox: Activates plug-in delay compensation for the MIDI output port shown in the Destination field of that row. This compensates for delays that can be introduced when using software plug-ins.
MTC checkbox: Activates the transmission of MIDI timecode for the MIDI output port shown in the Destination field of that row.
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.
MMC checkbox: Activates transmission of MIDI Machine Control for the MIDI output port shown in the Destination field of that row. These commands are then sent whenever you operate the transport functions (Start, Stop, Rewind, and so on) of Logic Pro.
Note: MMC will only be sent to the MIDI output destination if the Transmit MIDI Machine Control (MMC) checkbox is selected.
MMC is normally used when Logic Pro is receiving an external sync signal (for example, MTC or MIDI clock) from an external device (such as an ADAT), and you want to use Logic Pro to control the external device’s transport functions. Logic Pro therefore transmits MMC and receives MTC simultaneously. If you want to use the transport controls of the external device, you don’t need to transmit MMC. In this situation, Logic Pro only receives MTC from the transmitting device. You can also use MMC to record-enable tracks on the MMC receiver device.
Clock Mode pop-up menu: Determines the MIDI clock transmission mode for synchronized MIDI devices.
- Pattern - Quantized clock start based on pattern length: Sends a Start command to begin sequencer playback from the beginning of the pattern. The length of the pattern must be set in the “Clock Start: with a pattern length of ____ Bar(s)” field.
- Song - SPP at Play Start and Stop/SPP/Continue at Cycle Jump: Sends a Start command if playback begins at the start of your song. Otherwise, a Song Position Pointer and a Continue command are sent to begin sequencer playback.
- Song - SPP at Play Start and Cycle Jump: Sends a Song Position Pointer command when you start playback and every time Cycle mode repeats.
- Song - SPP at Play Start only: Sends a Song Position Pointer command only when you begin initial playback.
Clock Start: “at position” field: Defines the musical position at which the MIDI Clock output should start. 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.
Clock Start: “with a pattern length of ____ Bar(s)” field: When Clock Mode is set to “Pattern - Quantized clock start based on pattern length” use this field to select the length of the pattern in bars.
Transmit MIDI Machine Control (MMC) checkbox: Activates transmission of MIDI Machine Control to all MIDI output destinations with MMC selected.
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 devices receiving MIDI clock that are mechanically slow, such as reel-based tape recorders. Rather than having the machine play immediately, it’s asked to reach the desired SMPTE position before playback is started. There’s no noticeable difference in the response of Logic Pro to the Play and Deferred Play commands, because 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 device receiving MIDI clock (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 device receiving MIDI clock is perfectly located, without being in playback mode.
Save as Default button: Saves the current MIDI synchronization settings and applies them to all new projects.
MIDI Sync Preferences button: Opens the Sync tab of the MIDI Preferences window.

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Logic Pro User Guide

MIDI Synchronization settings in Logic Pro