General Synchronization project settings in Logic Pro for Mac
When Enable Complete Features is selected in Advanced settings, General Synchronization project settings are available.
The General Synchronization pane provides settings that determine how Logic Pro for Mac is synchronized, with what frame rate standard, and how the absolute time display (SMPTE) is linked to the bars and beats display.
Synchronization settings
These settings determine whether Logic Pro is synchronized to its internal clock or controlled by an external source.
Sync Mode pop-up menu: Defines how Logic Pro syncs with the other device.
Internal: Selects the internal timer of Logic Pro, with Logic Pro transmitting MIDI clock. External devices can be synchronized via MIDI clock or MTC.
Ableton Link: Selects Ableton Link mode, which uses a technology that synchronizes the musical beat, tempo, and phase of Logic Pro with multiple applications running on one or more devices on the same network.
MTC: Selects MIDI Time Code mode, with Logic Pro following incoming MTC. MIDI timecode can either arrive at a MIDI In port, or be generated by a MIDI interface that translates it from incoming SMPTE timecode—the Unitor8, for example.
Manual: Selects Tempo Interpreter mode, with Logic Pro receiving MIDI clock impulses that are recognized as valid beats by the Tempo Interpreter. The parameters that control how Logic Pro responds to Tap Tempo commands can be found in the Tempo Interpreter window.
Transmit and Receive Start/Stop checkbox: When selected, transport start and stop commands are shared between all Link users in a session who have the feature enabled.
The status of this checkbox is saved as an app setting.
Auto-enable external sync and Tap Tempo checkbox: When selected, Logic Pro transmits MIDI clock until it receives a synchronization signal—either in the form of MTC, or from the Tempo Interpreter.
Logic Pro automatically locks to the first synchronization signal it receives.
Important: Make sure that different synchronization signals don’t arrive simultaneously; remember that only one device should transmit timecode.
Frame rate settings
The time position along a project’s timeline is measured in hours, minutes, and seconds, where each second is divided further into frames (originated from film). The frame rate, based on a specific standard, is expressed as “frames per second” (fps).
Frame Rate pop-up menu: Defines the frame rate, which applies to both transmitted and received timecode.
Note: In drop frame formats, certain frames are left out. The SMPTE display uses a semicolon between the second and frame number to indicate drop frame formats (for example, 01:00:04;16). To distinguish between formats, those without dropped frames are sometimes referred to as non–drop frame (NDF).
23.976 fps: 24 fps running at 99.9%, which facilitates easier transfer of film to NTSC video
24 fps: Film, high-definition video
25 fps: PAL video/television broadcasts
29.97d fps: NTSC video/television broadcasts (drop frame)
29.97 fps: Standard-definition NTSC
30d fps: NTSC video/television broadcast (drop frame); rarely used
30 fps: High-definition video; early black-and-white NTSC video; an older rate that is rarely used today
50 fps: Higher frame rate based on 25 fps
59.94d fps: 60 fps running at 99.9% using drop frame
59.94 fps: 60 fps running at 99.9%
60d fps: Higher frame rate video standard using drop frame
60 fps: Higher frame rate video standard
Auto detect format of MTC checkbox: When selected (recommended), the incoming timecode is analyzed and the correct frame rate set automatically.
Note that it’s not possible to automatically distinguish between the 29.97 and 30 fps MTC (MIDI timecode) frame rates:
The MTC standard doesn’t allow a distinction.
A measured rate of 30 fps could also be 29.97 fps timecode running too fast, and vice versa.
Logic Pro automatically interprets frame rates of “approximately 30 fps” as either 29.97 (drop frame) or 30 fps (non–drop frame), depending on whether or not the drop frame format is used. This interpretation usually is correct, because these two formats are used as a standard.
The “Auto detect format of MTC” option only switches to 29.97 (drop frame) or 30 fps (non-drop frame) if one of the other conventional formats was previously set. If you want to synchronize Logic Pro to one of these nonconventional frame rates, you need to define the format manually. This setting isn’t altered by the “Auto detect format of MTC” function.
Validate MTC pop-up menu: Specifies how often Logic Pro checks for incoming timecode, in order to ensure synchronization integrity. In general, you should leave this option set to “Always.” There are some devices that generate timecode pulses that may require a specific number of frames to be set, in order to maintain synchronization.
Bar position vs. SMPTE time settings
The following settings determine the link between absolute time (SMPTE timecode) and relative time (bars and beats).
Bar Position Plays at SMPTE sliders: Defines the SMPTE offset for the project. Because projects don’t always need to start precisely at bar 1, you can select any bar position to be played at the set SMPTE time.
The default is Bar Position: 1 1 1 1 plays at SMPTE 01:00:00:00.
The SMPTE offset of 01:00:00:00 (one hour) is normally used, because it allows you to pre-roll an amount of timecode.
Enable separate SMPTE view offset checkbox: Shows the absolute time from the start of the project in the time display, rather than the actual SMPTE time.
Bar Position Displayed as SMPTE sliders: Becomes available if you select the Enable Separate SMPTE View Offset checkbox. Choose Bar Position 1 1 1 1 displayed as SMPTE 00:00:00:00 (preset). If necessary, you can set other view offset values here.
The Tempo List always shows the real SMPTE time, never the SMPTE View Offset. The SMPTE View Offset is used in all other windows (including the control bar).
Tip: It’s 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).