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Knowledge & practice

Controlling ChamSys from QLab

· · 3 min read

Small and mid-sized touring productions often create a working reality you won’t find in any textbook: you run lighting and sound at the same time, you have little infrastructure, and you still want a clean, reliable show.

Over the years we’ve looked after many productions with QLab at the centre. Audio, video, timecode, interval chimes, interval music, everything came together there. On the lighting side it was often ChamSys MagicQ: a solid, fairly affordable desk that tours well, sets up quickly and suits many independent companies.

Why we control lighting from QLab

Simple: QLab is the one system that always runs in sync during a show anyway. When we fire sound or video cues, we want certain lighting states to follow as precisely as possible:

  • a blackout at the end of a scene
  • an effect in a dance piece
  • an atmospheric crossfade
  • or a fade timed exactly to a musical accent

ChamSys can receive OSC and QLab can send it. The exact command list is in the MagicQ manual. The integration is basically very easy:

  • QLab sends, for example, /pb/10/go to MagicQ, meaning GO on playback 10
  • MagicQ fires a stored scene, a fade or an effect
  • both systems stay in the same running order

Especially on tour, when you’re in a different venue every night, it’s convenient to have the lighting sequences come straight from the playback system. It avoids timing errors and keeps the piece precise.

Why we use OSC rather than MIDI

ChamSys understands MIDI, and so does QLab. In theory MIDI would be the simple, obvious solution.

In practice we ended up with OSC, for three reasons:

  • OSC is network-based. Our lighting desk is on the network anyway because of sACN, so we need no extra cables and can use the infrastructure that’s already there.
  • OSC commands are more explicit. We can say exactly “start this cue” instead of just sending note 39. If we change the show structure later, the cues stay easier to follow.
  • We get feedback on the FrenschPress. It isn’t essential for the show, but it’s nice to have. The button tells us whether QLab started the cue and whether it’s still running.

We could also use the FrenschPress with QLab in MIDI mode, and that works perfectly. We just like the LED feedback in OSC mode.

What the setup looks like

A typical touring setup for us:

  • laptop with QLab (audio/video)
  • ChamSys PC or MQ desk
  • small switch or a direct network cable
  • FrenschPress in OSC mode, MagicQ and sound desk on the network
  • a few clear OSC commands from the FrenschPress straight to QLab, with QLab controlling the lighting desk

QLab sends OSC to MagicQ → the lights run. The FrenschPress sends OSC to QLab → playback and lighting start in sync. The LED feedback shows whether the GO arrived cleanly and the cue is running.

The setup stays stable from venue to venue. Assign the IPs and addresses once, and after that you only plug in the cables. How we build an address plan like that is in networking for show control.

These days we really like using this setup for:

  • small theatre productions
  • dance companies
  • comedy

Above all, during the show we can concentrate on timing and the stage instead of the system.