Moving head

A moving head is a motorised fixture on a yoke: the whole optical assembly rotates and tilts, and colour, beam size, focus and pattern are driven remotely from the console. Trade usage calls them movers, automated lighting or intelligent lighting, though the intelligence is in the programmer rather than the fixture.

They come in three functional types and the words matter when a rig is quoted. A wash has wide, soft coverage and mixes colour — it lights people and surfaces. A spot has a tighter beam, a gobo wheel and a focus, so it can project a defined pattern or a hard pool. A beam is the narrowest of the three, built to be looked at rather than to light anything: a visible shaft in the air. Hybrid fixtures combine two or three, and a spec sheet rather than a category name is what settles what a given unit does.

What catches people out is control channels. A multi-parameter moving head occupies twenty to thirty consecutive addresses, and extended modes more, so a single universe of five hundred and twelve channels holds roughly twenty of them. A rig of forty movers is a two-universe rig before a single conventional fixture is added.

The other cost is time. Movers have to be focused and programmed, and that is scheduled work in the day, not something absorbed between other tasks.

Event lighting — owned inventory, our own crew, and a site survey before anything is specified.

• DMX The control language every lighting fixture speaks — five hundred and twelve channels to a universe, a terminator at the end of the line, and a surprising number of shows undone by neither.
• Gobo A cut or etched template dropped into a fixture so it projects a shape — texture, a window, a pattern on a floor, or a logo — and sized by what fits the gate, not by the picture.
• Lighting console The desk that holds the patch, the looks and the running order — and the reason a show can be rebuilt in ten minutes when a speaker is moved up the programme.