Apple Logic Pro 7 - Manual (Page 613)

Chapter 19 Synchronization 613
Logic also obeys so-called “full frame messages”, and sets Logic’s song position line 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 in this case) to a new position, without implicitly starting playback. This is
useful when in slow shuttle or single frame advance modes with video machines,
because the slave device is perfectly located, without being in playback mode.
The MIDI Sync Preferences button launches the MIDI Synchronization preferences
window (see “MIDI Preferences: Sync” on page 648).
Unitor
SMPTE Mode
Here, you can instruct the Unitor8 to write SMPTE. You must switch from Read to
Generate, and set the frame rate and start-time in the “General” page. In Refresh mode,
fresh time code is generated in sync with received time code. “Refresh” works with both
VITC and LTC.
You should always use “Refresh” whenever you need to copy an LTC track, because you
cannot directly copy LTC without a considerable loss of quality. When copying whole
multitrack tapes, you should patch all tracks directly, but refresh the TC track via the
Unitor8.
You should only use Refresh mode if you are copying time code.
SMPTE Type
This is where you define the SMPTE format that you want to use:
LTC: Longitudinal Time Code is written to a tape track.
VITC: Vertical Interval (or Vertically Integrated) Time Code is written invisibly to a video
tape.
Freewheel
You can set the freewheel time in frames for LTC and VITC. The freewheel parameter
affects the SMPTE reader, and specifies how long the synchronizer continues
transferring MTC to the sequencer, after time code ceases to be read.
Long freewheel times can maintain synchronization, even if there are drop outs in the
time code, but they also increase Logic’s reaction time—after the time code master
stops. In practice, you should set the value as large as necessary (for sustained
operation), and as small as possible (for short waiting times).