QLab or GrandMA3: Which One Should Be Master?

It Is Not a Product Comparison

People arrive at this question expecting a verdict on QLab versus GrandMA3. That framing does not survive contact with the problem, because both are excellent and they are not competing — they do different jobs and both happen to be capable of owning a clock.

The real question is architectural: which system is the authority on where the show is? Everything else follows.

The Deciding Question

If the other system stopped right now, which department would have to improvise?

That department should be master.

QLab as master when sound and video carry the show. The audio has a transport, the transport knows its position, and lighting is following what the audience is hearing. This is most musicals, most devised work with heavy playback, most corporate keynotes. QLab generates the clock; the console chases.

GrandMA3 as master when the show is lighting-led. It starts because the board operator presses GO. Sound is support, not spine. This is a lot of dance, concert-style work, and anything where the lighting is the primary storytelling instrument. The console owning its own clock removes the external cable, the second machine, and the entire "which box is master" class of fault.

Note that neither answer mentions which product the team prefers, and that is deliberate.

Two Masters Is Not a Compromise

It is worth being blunt, because this is the failure that actually happens.

Two clocks live at once means two authorities on show position. They will agree in rehearsal. They will agree at the tech. They will disagree the night something restarts, or a frame drops, or an operator jumps a cue — and when they do, nothing in the system can adjudicate, because you built it with no tiebreaker.

The legitimate version is one master per segment with an explicit handover: a defined seam, a visible indication of which system is in charge, and an operator who can force the changeover. The illegitimate version is two generators running concurrently because nobody wanted to have the conversation.

Choosing the Link

Once the master is decided, the transport is a smaller question — but it is a real one.

The distinction that matters: timecode lets a follower recover on its own. A console chasing timecode that loses the signal for two seconds and regains it knows exactly where it is. A console that missed an MSC GO has no idea it missed anything, because there is no acknowledgement in either protocol and only timecode is self-describing.

That property is why timecode is worth the extra setup on long, continuous shows, and why MSC is entirely sufficient on shows that are a sequence of discrete moments.

Where CueSync Sits

If the show has a timeline and one of these two owns it, CueSync is not required for the link — QLab and GrandMA3 can talk to each other directly, and a system that does not need a third component should not have one.

It becomes relevant when there is no timeline to own: a band, a DJ segment, an improvised passage. Nothing can generate timecode by reading a transport when there is no transport. In that case position has to be derived from the performance itself, and CueSync chases CDJ position, MTC, LTC or TCNet with priority-based selection, then generates MTC, LTC, Art-Net timecode or TCNet outward — so the rest of the rig keeps a normal master to follow.

It also speaks to both ends directly: OSC and MSC to QLab, OSC over TCP or UDP to GrandMA3. On a hybrid show that is often the seam — scripted segments mastered by QLab or the console, unscripted ones derived from the music, with a deliberate handover between.

Before Opening Night

Write the master on the plot. Not in someone's head. The crew that loads in at the next venue will not have been at this conversation.

One frame rate, declared everywhere. Set it on the generator, then verify on the consumers rather than assuming inheritance. 29.97 against 30 drifts about a frame every 33 seconds — invisible at the top of a show, unmistakable by the end.

Pull the cable in rehearsal. Decide whether the follower freezes or freewheels, make sure the operator can see which is happening, and have them practise the recovery once, while it is still cheap.

Further Reading

• Where Should Your Show's Timecode Come From? — all four architectures
• How to Send Timecode to GrandMA3 — transports and frame rates
• MIDI Show Control Explained — the discrete-event alternative
• QLab Integration · GrandMA3 Integration