|Wrecking Crew Orchestra - Cosmic Beat Behind the Scenes||| Print ||
|Written by Akiba|
|Monday, 09 December 2013|
Last week, Wrecking Crew Orchestra wrapped up their Cosmic Beat show which I helped out with. There were six performances in total, three in Osaka and three in Tokyo and it was a blast working on it with them. They recently published the opening set from the show which featured Wrecking Crew Orchestra, EL Squad. This was the group that made a big splash with "Tron Dance" in 2012.
The Cosmic Beat show used quite a bit of modern stage technology including projection mapping and laser graphics. For projection mapping, they were using two 20,000 lumen projectors for the set projection and worked with a VFX company on the graphics for the mapping. We also worked with Shinichi Suzuki, aka "Laser Master", from Akari Center in Tokyo who did the laser work and normally does large concert venues. He's a topnotch laser guy and I learned a lot from him about how to operate lasers and laser scanners.
I was working with them on two separate parts of the performance. The first was the EL wire controllers for EL Squad and the second project was wirelessly controlled power LEDs that were used in the production. The EL wire system consists of two parts, a transmitter which is attached to the main show computer, and receivers which are worn by each dancer.
The receiver is a custom design which combines a 900 MHz radio, Arduino subsystem, battery management/power supply, and EL wire switching. The whole thing is enclosed in a ruggedized case to survive the heavy vibration due to the dancers' movements.
The receiver has three inverters which are enough to power about 30m of EL wire. Each dancer walks around with approximately 20 to 25m of EL wire. Because of this, I also had to design the power supply to handle high currents since the wire consumes quite a bit of power when all the wire is on.
I had to tweak the brightness of the system quite a bit and actually overdrive the wire a bit to make it stand out more. Since we pump a lot of current through the wire, the wire often burns out. The dancers in Wrecking Crew had to implement a quick change wire system since there are times in the middle of a show where a dancer's wire needs to be changed out. They've got it down to an art form and are like a pit crew in racing. At the rehearsals, some dancers cut the EL wire to the correct lengths and solder on the connectors, while others manage the repair and maintenance of the costumes. They also maintain an inventory of each color and length so they always know which wires need to be made.
There are approximately 12 to 24 dancers in EL Squad at any time and maintaining the equipment for all of them through rehearsals and shows are crazy. The battery management alone is almost a full time job since we need to make sure nobody runs out of batteries in the middle of a performance. This was actually a problem we ran into when we first started using the system. For rehearsals, we use rechargeable Li-Po batteries and I designed a special gang charger to quickly charge large amounts of batteries so that we'd have a steady supply of batteries for long rehearsals.
The transmitter side was difficult too. The theater environment is an extremely harsh environment and probably one of the nastiest, noisiest environments I've ever worked in. There are multi-kilowatt stage lights that are being dimmed and the triac dimmers cause horrible wideband noise. We ended up having to do a lot of work to get the signals to the dancers reliably. I set Wrecking Crew up with a portable spectrum analyzer and they now do site surveys of the theater to check out the ambient noise. The site survey is used to determine the best channel to use for the system. I also had them switch from using omnidirectional antennas to high gain directional antennas since we normally need to transmit signals from the control booth in the back of the theater to the stage. Getting there usually requires going through a wall of thick noise due to the stage lighting and sound system. The complete system is fairly sophisticated and many of the dancers in Wrecking Crew area actually quite knowledgeable about wireless communications and RF propagation now. Trial by fire. Ha ha ha.
Here's a shot of some of the transmitters, spectrum analyzer, and antenna.
The final system is pretty complex. It actually took about six months to come up with the initial transmitter and receiver design but thenanother year to stabilize and tweak the design to make it perform consistently through various theater venues. Overall, it's an amazing experience to work with such great dancers and I learned a lot about the tough world of show control technology. It's really fascinating and I'll definitely be doing more designs for live show control and will be working closely with Wrecking Crew for many other performances :)
p.s. I get this a lot. People automatically assume that the EL Squad dancers are guys. Actually, most of the EL Squad dancers are female. Also, here's some raw footage I took of the opening sequence during one of the dress rehearsals. The view is slightly different than the original version since I'm in one of the audience seats and not the control booth. You can also hear the raw audio rather than the clean version.
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