How many times do you wish that you could easily control a practical on stage? You know that trying to rely on the actor to get it right or timing the cue to look accurate can sometimes prove impossible. What if the actor is carrying the practical all over creation, and the director refuses to have a cable dragging behind? Well, there are products available from City Theatrical and Soundsculpture that let you take back control as well as open up many new possibilities for design freedom. The systems are being expanded as more applications come along. This is a closer look at these two wireless dimming systems.

Setting up a wireless dimming system is quite similar to setting up any DMX-based system. The key thing to remember is that the wireless transmitter and receiver essentially replace the DMX cable. DMX control data from any standard DMX console is input to the transmitter, which converts that DMX data to a radio signal and broadcasts it to the receiver. Here is where the City Theatrical and Soundsculpture systems begin to differ. The City Theatrical WDS receiver gets the radio broadcast and converts it back into standard DMX data, which can then be connected via standard cables to WDS 15A Dimmers or other devices such as moving lights, effects, etc. The WDS Personal Dimmer is, however, a dimmer and receiver in one small package. The Soundsculpture RC4 system combines the receiver and dimmer into one unit, so it doesn't convert back to DMX at the receiver. It was conceived as a wireless dimming system. (Recently, Soundsculpture has added this capability to the system with its RC4-RX4-DMX receiver.)

The WDS Wireless Data System from City Theatrical is a modular system that started out as the Wireless Dimming System and has morphed into the Wireless Data System with the addition of wireless DMX-only products that expand the range.

“The core [WDS] product is a 15A DC dimmer that controls up to 24V. So with a 24V power supply, it is a 360W dimmer,” says Larry Dunn, head of engineering for City Theatrical. “With a 12V power supply, it is a 180W dimmer. That is because it is current-limited, not voltage-limited. It is fused at 15A. If you do more than that, the fuse will blow. The next is the Personal Dimmer, a battery powered, tiny unit with a receiver and a dimmer built in, so you can wear it with costume lighting.” Its power is 9 to 12V DC, 100mA battery power. The small dimmer is 3.3"×4.3"×.8125", so it can be easily hidden in a costume or small prop. “Then we have made — on a custom basis — 30A dimmers. We can do that at any time people want it. There isn't really a call for the larger loads. Usually, people want more points of distribution.”

“With the current system, we get 32Hz refresh before we start having any data issues,” says Dunn. “That is as fast as an [ETC] Expression 3 or a [Flying Pig Systems] Wholehog 2. The way the system works is that it receives the DMX and then it converts it to a 2.4GHz spread-spectrum frequency-hopping signal and broadcasts it over the air to a receiver that is configured to receive that and turns it back into DMX and outputs from the receiver as regular old DMX.” The 2.4GHz spread-spectrum channel hopping technology ensures the delivery of mission-critical data that the entertainment industry demands. This technology comes out of military/industrial uses.

Every dimmer has a full DMX address interface, so you can set any dimmer to any DMX value. There is no patch massaging. The dimmers will also do non-dim functions, so you can use them to control events. The wireless system can handle up to 32 wireless ID channels.

Soundsculpture's RC4 Wireless Dimming system was designed as a dimming system and not a wireless DMX data system. The RC4 system consists of two transmitters, which are spread-spectrum digital radio transmitters that encode 32 or 64 channels of DMX for output to RC4-RX4 radio dimmers. On the receiver end, the dimmer units connect directly between a battery and up to four loads (lamps, motors, relays, etc.). A battery powers the radio, logic for dimming control, and the load.

The RC4 dimmers come in three models. “The smallest one, the RC4-RX4-Mini, is a total of 200W balanced over the four 50W channels,” says James David Smith of Soundsculpture. “You can gang them so if you wanted to do one 200W load, you could set it up as one large dimmer or any combination thereof. The middle unit is the RC4-RX4-Standard, a 500W dimmer. The largest is the RC4-RX4-HO. Each of the four outputs can handle up to 250W, and the total package can handle a full 1,000W. It's a 1kW dimmer that is wireless. All of the RC4 receivers are gangable.”

If one requires more output channels, multiple receivers can be used — up to 127 receivers with each RC4 transmitter. The RC4 system limits channel counts of 32 and 64. “Technology-wise, I had to make a decision about offering a complete universe of DMX or using all that bandwidth to improve my reliability,” Smith explains.

In November at ETS-LDI, City Theatrical will be expanding its WDS product range. “In addition to the core WDS-line, we also have an OEM receiver that can be built into other gear,” comments Dunn. “We are going to be launching some new equipment that is going to have that built in, so you will see more City gear that has built-in WDS reception. We have other companies that are looking to incorporate the WDS OEM receivers into their various products — more things that can talk WDS as well as wired DMX.”

Dunn also is keeping a close eye on RDM, as well as other control that may come along. “Our equipment is designed with the idea that we can convert to RDM. We are watching RDM very closely. The hooks are built into the design already. Once something like that is adopted, you will see it as having a lot of power. All of our radios are transceivers, which means that all of the gear can do bi-directional data. We also have a range of special antennas and site-specific software that we can provide. We are always trying to make the stuff better.”

Soundsculpture will also be releasing new products at ETS-LDI. “I am introducing a sliding-scale system,” says Smith. “Instead of making you choose between 32 and 64, you will be able to choose how many channels you want. When you get up to 83 channels, you are at the same update rate as DMX; at 115 channels, you are at 32 updates per second, which is still better than most consoles, where they are doing 30 frames per second.” Currently, Soundsculpture's system gives 32 or 64 channels and keeps a high update rate of 100 updates per second; that is the redundancy, the reliability, and the speed. “It will go all the way to 128 channels, which at that point, you are running kind of slow,” continues Smith.

At ETS-LDI, Soundsculpture will also debut Reference Voltage Dimming, which will allow the use of batteries with a higher voltage than 12V but will be able to drive 12V. “This is interesting because there is a variety of power tool batteries and chargers out there,” says Smith. “We have put software in the dimmers that detects the voltage and adjusts the output power, so that if you are driving a 12V motor or lamp, only 12V comes out, and you have the full dimmer range.”

Another new feature Soundsculpture will introduce helps smooth out the fades when dimming LEDs. “The problem that a lot of designers have with LEDs is that they look too digital,” says Smith. “If you watch them dimming, you can see them step through the increments; they are very abrupt. We do some software simulation in the dimmer that lets you use an LED with a very brief ramp-in and ramp-out effect that matches what an incandescent lamp does naturally.”

The possibilities for wireless dimming are endless. Designers now have the freedom to have controllable lighting in costumes, props, scenery, as well as to put lighting in places that were previously impossible to reach. Plus, the ability to control motors and relays opens up even more possibilities. Both companies see future technologies and products coming along that will make their products stronger and more flexible. And, as volumes increase, costs go down, making wireless dimming accessible to a wider audience.

Test Driven: User Feedback on Wireless Dimming

Both City Theatrical and Soundsculpture wireless dimming products are used on shows that range from Broadway to regional theatres, from opera to events. There are now quite a few wireless dimming channels at work. Here is some feedback from two users on how things are going:

On City Theatrical's Wireless Data System:

“I think that the City Theatrical WDS system is really solid. I was a fan of the Logical Lighting products that we used on Hairspray in New York, but you couldn't get the parts for it anymore. Larry [Dunn] and Gary [Fails] were working on the WDS products at that point, so when I was preparing the Hairspray tour, I switched it all over to the WDS products. We used 30 of the 15A dimmers on the tour. I also switched all of Hairspray NY to City Theatrical WDS. The Logical product was based on radio control car technology, which worked great, but the components were overheating and burning up. The WDS products hold up great; they have been out on the Hairspray tour for two years. They are rock-solid. The transmission from the transmitter to the receiver is wonderful. I have had very few interference problems. The wireless DMX also comes in handy for gobo rotators out on the balcony rail. I put the transmitter at the proscenium, and they run great. The WDS is all modular, small, and lightweight. I Velcro them onto a board, so if there is ever an issue, I just unplug it, un-Velcro it, and pop another in place. City Theatrical really did it right. Larry and Gary asked a lot of questions and really listened to the electricians and what they needed in the product, but then that's the story of the company. I am one of their biggest fans.
Production electrician Mike LoBue

On Soundsculpture's RC4 Wireless Dimming:

We first started using the system last December. So far I am in love with the system. We had a previous wireless system that was basically a modified radio airplane controller; this is so much cleaner, so much slicker. It interfaces directly with our DMX. Our old system was very unreliable. It took hits, so we had lights flashing on and off when we didn't want them; that has never happened with this system. This system has been rock solid. The opera owns four of the Mini-Receivers and one High-Output receiver. The Ballet owns two of the Standard Receivers. We have two planes that use the RC4 dimmers. One is a small model bi-plane that sails across the front of house area on wires, and we have lights in the wing tips. The second is a medium-sized plane that flies across upstage, and we are using the system to actuate a solenoid that allows some hot water to drop into dry ice for a contrail effect. That plane actually gets shot down. Sometimes, we like to have manual control and run the units off a Lil'DMXter or small controller. Normally, we interface it through our Strand console.”
Jim Caudle, assistant master electrician for the San Francisco Opera and Ballet, currently using RC4s for a production of Rossini's The Italian Girl in Algiers