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Chapter 18 Synchronization 457
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 MIDI Clock Delay
This parameter allows you to delay the transmitted time code. Negative values mean
that the MIDI Clock signal is transmitted earlier. This enables you to compensate for any
reaction delays in external MIDI Clock slaves.
Transmit MTC (MIDI Time Code)
The checkboxactivates transmission of MIDI Time Code. The pull-down menu
determines the MIDI output port for the MTC signal.
It is not advisable to send MTC to all ports. MTC is very data-intensive, so use a MIDI
port that isn’t being used for anything else.
Transmit MMC (MIDI Machine Control)
This is where you can switch on transmission of MIDI Machine Control (see “Sync
Problems and Solutions” on page 460). These commands are then sent whenever you
operate Logic’s transport functions (Start, Stop, Rewind, and so on).
MMC is normally used when Logic 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.
Logic 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 will follow the MTC master as a slave.
You can also use MMC to place tracks on the MMC slave device into record-enabled
mode.
Listen to MMC Input
Logic can be controlled by MMC (MIDI Machine Control) and so-called “Full Frame
Messages” (Listen to MMC Input). Transmit MMC has been available in Logic for quite
some time.
Logic 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. You’ll find no
difference in Logic’s response to the play and deferred play commands, as Logic can
locate as quickly as any hard disk recorder.