Apple Logic Pro 9 - Manual (Page 1291)

MIDI Sync Preferences
The Sync pane contains the following preferences:
• All MIDI Output: Delay field: Delays or advances the MIDI output for all ports, allowing
you to compensate for any timing differences between MIDI tracks and audio or
(software) instrument tracks.
• MIDI Clock: “Allow to send Song Position Pointer while playing” checkbox: Song Position
Pointer (SPP) data is not normally sent while the sequencer is in Playback mode. (This
is in accordance with the MIDI Standard.) This option allows Logic Pro to send SPP data
while the sequencer is running. The advantage is that external devices can also follow
Logic Pro in Cycle mode. If your external devices cannot process SPP, you should turn
this option off. If your devices can follow MTC (MIDI Time Code), you should leave this
option unselected, and use the MTC functions of Logic Pro.
1291 Chapter 44 Preferences in Logic Pro