10.6

Table Of Contents
1040Logic Pro User Guide
Tip: Its common practice in many video (and audio) post-production houses to set
a one-hour SMPTE offset (01:00:00:00). This avoids a problem commonly referred to
as midnight, where a pre-roll passes through SMPTE time 00:00:00:00, which causes
issues with some tape machines (such as the ADAT).
Audio Synchronization settings in Logic Pro
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 machine transmitting timecode to the nominal value (the
same speed used when the timecode was recorded). Adjust the varipitch control on the
transmitter 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 doesn’t allow any variation in the sample rate.
Deviation slider: Shows the current phase deviation of the Word Clock from the
timecode transmitter—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 transmitter 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 works even when recording while receiving MIDI clock.