MMC transport sync between two DAWs, explained

When two people track together in the same room, one person runs the transport — they hit play, everyone plays; they stop, everyone stops. Do the same thing over the internet with two separate DAWs and it falls apart fast: “okay, three, two, one, go” over a call, both of you stabbing spacebar, never quite together. MMC transport sync fixes that by letting one DAW drive the other. This guide explains what MMC is, what actually follows across the link, and why it matters more for remote work than most people expect.

What MMC actually is

MMC stands for MIDI Machine Control. It’s a small, decades-old part of the MIDI standard designed for exactly this problem: one device commanding the transport of another. It predates the internet era — it was built so a mixing console or a sequencer could drive a tape machine’s play, stop, and locate. The commands are tiny and universal: play, stop, record, and locate (jump the playhead to a specific position). Because it’s a command protocol rather than a stream of audio, it’s light and fast — you’re sending “go to bar 33 and play,” not the sound itself.

Every major DAW already speaks MMC, because it’s how they’ve always talked to outboard machines and to each other. SessionLinked uses that same well-worn language to keep two remote sessions’ transports locked together, so you’re not inventing anything exotic — you’re using a protocol your DAW has understood for years, carried across the link.

What follows across the two DAWs

With transport sync active, one person is the driver and the other’s DAW mirrors them. Here’s what travels:

1. 1
   PlayHit play on the driving DAW and the other DAW starts playing too — from the same point, so you're both hearing the song from bar one, or bar 33, or wherever you started.
2. 2
   StopStop on one side and both stop. No more one person still rolling while the other has already hit space and started talking over the outro.
3. 3
   LocateDrag the playhead or jump to a marker on the driver, and the follower's playhead lands in the same place. You say “let's take the second chorus from the top” and you're both already there.
4. 4
   RecordArm the take and roll record on the driver, and the follower engages record in sync — so the person tracking doesn't have to also operate the transport. They just play.

The effect is that the whole session feels like one machine with two keyboards. Whoever’s producing can drive from their chair while the player concentrates purely on performing — which is exactly how a session works when everyone’s in the same room.

Count-in and “wait for signal”

A detail that separates “it technically synced” from “the take is usable” is how recording starts. Punch in cold and the player has no time to catch the tempo; the first bar is always a write-off. Two mechanisms handle this.

A count-in gives the agreed lead of a bar or two of clicks before the transport reaches the punch point, so the player enters already in the pocket — and because the transport is synced, that count-in is shared, not something each side sets up separately and hopes lines up.

“Wait for signal” handles the network reality: rather than starting the instant a button is pressed, the follower can hold until it has confirmation that both sides are armed and locked, then begin together. Recording starts at the right moment for everyone, instead of one side jumping the gun because a command arrived a fraction early.

Why this matters for remote tracking

Without transport sync, remote recording is a two-job task: you’re performing and coordinating the transport by voice, and the coordination always loses. Every take starts with a countdown that doesn’t quite land, and comping across takes means manually re-aligning what each side captured at slightly different moments. With MMC sync, the producer drives, the player plays, and every take begins cleanly from the same position — so the files that land on your timeline already agree on where bar one is. That’s what makes remote tracking feel like a session instead of a phone call with instruments.

In SessionLinked, MMC transport sync rides on the same single plugin you insert on your Stereo Out — there’s no separate device to configure. Hosting DAWs that fully host the Audio Unit (Logic, Reaper, Ableton, Studio One) get automatic record detection and transport sync; the setup guides note exactly what each DAW supports today, honestly. Pair the sync with lossless take delivery and you have the full remote-session workflow: play together in time, and keep the real files.