Apple Logic Pro X - Manual (Page 876)

Chapter 25 Preferences, project settings, and key commands 876
Audio Synchronization settings
You can use Audio Synchronization settings to keep your audio and MIDI tracks synchronized.
When Show Advanced Tools is selected in Advanced preferences, the following are available:
•
MTC slider: Shows the deviation between the incoming MTC and its nominal frame rate.
If the deviation is significant, make sure that the correct frame rate is set in the General
Synchronization pane. If in doubt, set the frame rate to 24 fps and select “Auto detect format
of MTC” in the General pane. If the frame rate is correct, you can use this display to adjust
the tape speed of the master machine to the nominal value (the same speed used when the
timecode was recorded). Adjust the varipitch control on the master machine, until the slider
is centered.
•
Sample Rate slider: Shows the deviation of the sample rate from its nominal value. Note that
some audio hardware does not allow any variation in the sample rate.
•
Deviation slider: Shows the current phase deviation of the Word Clock from the timecode
master—in other words, the deviation between audio and MIDI. Varying timecode signals
shown in this display indicate how Logic Pro regulates the sample rate of the hardware when
in MTC Continuous sync mode. Even large timecode variations result in no deviation between
audio and MIDI synchronization. Your audio hardware must be capable of continuously
variable sample rates for this to function. Small deviations between audio and MIDI are
unavoidable, because MIDI can (and should) follow the timecode master directly.
Note: The real-time sample rate conversion feature of Logic Pro allows it to follow an external
MTC signal (MTC Continuous), while maintaining the correct audio playback pitch and speed.
This feature even works when recording in MTC-slave mode.