Dimmer systems for stage lighting have always contained an element of voodoo.
The number of things that can inexplicably fuck up in this seemingly simple system are mind-boggling. Lamps come on and turn off for no reason, lights that worked yesterday refuse to turn on today, parts of the system shut off randomly, the console decides it doesn’t like the producer’s shirt (or something) and refuses to boot up. Older types of DMX cable will malfunction if run too near power cable, or will just decide not to work (or something) on any given day. Add moving lights into the mix and things get even more unpredictable (I have – more than once – seen grown men brought to tears by Vari-Lites).
On more than one show, we’ve replaced random parts to no avail, and someone on the lighting crew has somehow ended up in the dimmer hut*, wearing nothing but a grass skirt and the skin of the slowest-moving PA while scattering chicken feathers over the dimmer racks in an attempt to get something – anything- to work before the DP blows a gasket.
At Saturday’s seminar – which was attended by reps from the two companies who make dimmer racks, we learned that one company’s racks have the cool air intake on the bottom of the rack and the hot air exhaust on the top of the rack, and the other company’s dimmer racks have the exhaust on the bottom of the rack and the cool air intake on the top of the rack.
This means that the two company’s dimmer racks, when placed next to one another, are sucking in each other’s exhaust and overheating despite the air conditioning in the dimmer hut.
Oh. My. Gods. I did not know this, and apparently neither did either company’s reps (or anyone else) until fairly recently.
Lining up dimmer racks from both manufacturers next to one another is common practice – depending on how many racks one needs and how busy the town is, it sometimes isn’t possible to get only racks from one manufacturer.
Wait. Did I mention that the dimmer racks overheating is bad? I didn’t? Well, it is. It’s very bad (when they overheat they shut off and so do the lights they control, even if it’s in the middle of, say, a difficult stunt or the only good take of two actors who loathe one another pretending to make sweet love) and it happens more often than we’d like – and now a whole seminar full of people know exactly why.
Even if I hadn’t learned anything else from the day, that one thing was totally worth it.
*Dimmer racks contain fans, and fans make noise. Sound guys hate noise, so we can’t put the racks on the stage. We can’t put the racks outside with no protection from the elements because they really shouldn’t get wet or sit in the hot sun, so we put them in a little hut (usually a cargo container) right next to the stage.