Every computer system/DAW has an internal clock that keeps track of what events occur at any given time. Most of them can generate their own clocks, as well as receive an external source as a master clock. It’s essential that devices expecting an external clock can sync to the master clock, or your timing becomes a train wreck.
Regarding sync protocols, the main choices are SMPTE, MTC, MIDI clock, and MMC. Which one(s) you use depends on your circumstances and gear, so let’s check out each type.
• SMPTE (“Society of Motion Pictures and Television Engineers”) is one of the oldest sync protocols. It is independent of musical tempo, as it marks events based on hours, minutes, seconds, and frames (H:M:S:F). With early MIDI systems, SMPTE code was recorded on a tape recorder’s outside track (to minimize crosstalk), and a standard audio cable took the output to a MIDI interface. This decoded the signal to provide timing information to sequencers. SMPTE is still in use in film and video today, but is embedded in digital video files instead of recorded on an analog audio track.
• MTC (MIDI Time Code), the MIDI equivalent of SMPTE (Figure 1), is also independent of musical tempo and also displays elapsed time in H:M:S:F.
• MIDI clocks include no position or timing information, but simply provide a timing reference, like a metronome. Devices follow these clocks to sync to tempo, while additional commands tell a device when to start, stop, and continue. This is perfect for syncing synth and sampler LFOs, delay times, arpeggiators, drum loops, and other time-based sounds to a master clock.
• Song Position Pointer (SPP) can be transmitted along with the MIDI clock signal; it keeps track of how much time has elapsed during a tune in bars, beats, and subdivisions of beats (called ticks or clocks, which are the finest resolution of the MIDI device). Sometimes all you need is MIDI clocks and SPP rather than MTC or SMPTE, unless you must lock certain events (e.g., sound effects) in a sequence to absolute time instead of musical time.
• MIDI Machine Control is a system of controlling (play, stop, etc.) external gear, such as video tape decks, via MIDI.
Which protocol is best to sync everything together depends on the hardware involved. Some devices will not handle MIDI clocks, while musical instruments may not recognize SMPTE.
Fortunately all this work can be frame-accurate, so if you get a video file to work with on your computer, you can create the score, bring your laptop to the studio, and sync your computer to the studio’s system. This lets the main engi...