Martin Professional Stagebar 54 LED Luminaire
Light emitting diode (LED) fixtures are today an inevitable part of many designs. However, I have not seen a lot of RGB LED units that were 1.) bright enough or 2.) able to function as little more than an effect light to throw some color around. Of late, there are manufacturers who are adding amber or white LEDs to the red, green, and blue LEDs for a better color mix and the diode manufacturers are increasing the brightness at a quick pace. Combining the latest in LED technology with cutting-edge luminaire design, Martin Professional has gotten into the game with its first LED luminaire, the Stagebar 54 LED, which was launched in March 2007. I thought that it was time to take a more in-depth look at this unit.
The color mixing of the LEDs in the Stagebar was one of the first areas that the Martin R&D department focused on. “When we designed this fixture, we put a lot of effort into the color range,” says Morten Kristensen, product manager, Effect Lighting at Martin. “It is one of the reasons why we added the amber and the white LEDs. That is definitely a benefit and something that has been well-received from the market. We also worked to create absolute color in terms of our color calibration. We have four different modes to control color. Three of the modes use what we call color calibration, so each unit is calibrated from the factory. Meaning that in those three modes, you will always achieve the same color. We have a very narrow selection of the different LEDs, but we also do a color calibration with our own software. Each LED is measured and those values are stored inside of the unit. So when running them in these three modes, you will achieve uniform colors within the individual unit, but also between multiple units.”
A Focused Inspection
The three color-calibrated modes in the Stagebar 54 are HSI (Hue, Saturation, Intensity), which is a more intuitive method of mixing colors. You set the color you want by scrolling through hues (red, orange, yellow, green, cyan, blue, and violet), altering their saturation from deep to white, and finally changing their intensity from bright to dark; HSI-C (HSI with Color Temperature), which adds color temperature control to HSI; and RGB, which uses only three channels to approximate a standard RGB output based on all five colors. The last mode is RGBAW (Red, Green, Blue, Amber, White), which uses five channels to control each color independently. In this mode there is no color calibration. In all the modes, I found the units very bright and the colors mixed smoothly.
Many people mistakenly think that there is no heat involved in an LED fixture, but there is, and this is where many manufacturers miss the mark and shorten the life of the LED. The engineers at Martin spent time on the heat management as well as staying within the specification of the Luxeon K2 LEDs. “We run them within specification,” comments Kristensen. “That is a way that we can assure that we live up to an acceptable lifetime. We also put a lot of focus on the die temperature. When we promise 30,000 hours; you can believe that it is 30,000 hours. We don’t go out and promise 100,000 hours, because we know that is an unrealistic promise.” Martin has built in temperature monitoring as well as on-demand fans to regulate cooling. There are two modes for the fans; one where the fans run constantly at full speed and there is a fan-regulation mode where, depending on the ambient temperature, the fans will increase or decrease in velocity. I didn’t find the fans to be too noisy for most applications, including church services.
The Stagebar comes in two versions, the 54L (for Long) and the 54S (for Short) with the 54L measuring 24.8 inches (630mm) long and the 54S coming in at 16.5 inches (420mm). Both units are 7.5 inches (190mm) deep and 4.1 inches (105mm) high. There are 54 LEDs in both, but they are placed closer together in the 54S. The 54L is designed to keep the same pixel pitch (the distance between pixels) so you can stack these units vertically for video over LED effects. Without the mounting bracket, the 54S weighs 12.1 pounds (5.5 kg) and the 54L weighs 16.1 pounds (7.3 kg). The Stagebar 54 is equipped with an auto-sensing switch mode power supply and is compatible with all worldwide voltages. It ranges from100-240V nominal, 50/60 Hz. The Stagebar is UL and CSA listed for the United States and Canadian markets as well as having numerous European safety listings. The 54S has a list price of $2,499 and the 54L lists for $2,799.
The 54 LEDs are split into groups of nine LEDs in six compartments. Each compartment has an LED array consisting of two 1.2W red, two 2.9W green, two 2.9W blue, two 1.2W amber, and one 2.9W white LEDs. These are all Luxeon K2 LEDs. There is a detachable lens over each LED array and one clear lens over the whole front of the unit. This arrangement offers a 29-degree beam spread Half Peak angle. You can remove the clear lens as well as the individual lenses and put on a milk-white piece of Plexiglas as a diffuser. There are reflectors around each compartment to aid in the light output with the white diffuser option. (With the clear lens set-up, the reflectors serve no purpose.) The unit was originally designed as a color effect light, which is what the white diffuser is good for.
The Stagebar unit has an on-board power supply with a simple control pad on the rear of the unit as well. There are power and data in connectors on one side of the unit and power and data out connectors on the opposite side. This makes it very simple to daisy chain units together next to each other—either in a row for front light or cyc washes or stacked vertically for effects. The power connectors are Neutrik PowerCons, so they lock into place. For the data connectors, the designers at Martin chose to go with RJ45 connectors, which also use a locking, ruggedized connector for protection. When asked why they went away from the DMX standard of five-pin XLRs, Kristensen responds, “The reason for that is that we have added features, which would not be possible with an XLR connector. We have features like auto-addressing, where you can connect up to 32 units and from one unit you can auto-address all units. You can also copy different settings. From this feature, you can go in when they are all linked up and set the first one to RGBAW mode and copy pixel grouping No. 1 to all of them. This will save a lot of time. We needed the few extra pins, so that is why we chose the RJ45 connector.” The built-in controller also comes with a battery for setting up the units, pre-programming modes, and addressing the units. This allows you to set up a number of the fixtures without powering them up. This will be a great feature for a large production or a rental house.
I did find that there was a delay on power up when it takes time to initialize all of the onboard data. Kristensen comments that, “This question has been brought up a few times. This is because we have six pixel boards in the unit and every time you power up they have to be initialized and addressed. Even though there is no mechanical hardware that needs to reset, it does takes a bit of time to initialize.”
The unit comes with a very elegantly designed base, which can be used as a floor stand and has a locking mechanism to lock the unit in place for use as a footlight or tilted up for a cyc light. The unit is easy to focus and adjust. While a bit heavy at 16 pounds, for the 54L version, its size at just under 25 inches makes it very easy for one person to move, place, and adjust the unit’s focus. Many longer striplights really take two people to handle, especially trying to maneuver with floor trunnions and to get the right tilt locked into place, but the Stagebar is a one-person job. Also, with this length it is easier to accommodate a curved stage with the units, as well as to be able to tuck them in and around scenic elements. Like other Martin fixtures, there are fittings on the back for their Omega brackets, which is standard with many of their moving head units. You can use the Omega bracket with a half-coupler for truss mounting or with the floor stand bracket. They mount with two quarter-turn fasteners.
A Visual Director’s Perspective
I don’t design and work with lights on a regular basis, so I wanted to include some thoughts from a working designer who has used them in a real-world application. Ryan Slaughter, visual director for the band Mercy Me, is currently touring with 24 Stagebars as a main part of his rig and he was happy to discuss why he chose the unit for this tour. “It all started when we couldn’t fit a downstage truss in our pack. We had a one-truck tour and had to make room for audio, a backline, LED walls, and all of the lighting that we could shove into 16 feet, basically. The Stagebar made it easy to lose the downstage truss and put some light on the band from a footlight position. I also used it to backlight some risers and basically fill in the gaps. We are an all backlit show, completely backlit with a 40-foot-wide Martin LC2140 LED Wall and one 40-foot upstage truss with 12 Martin Macs. Granted, we ran the video wall at 50%; the Stagebars competed well with the LED wall. It made a good balance. I knew that we were going into churches and small rooms and I didn’t want to put in a bunch of Genie lifts. We were trying to go for a low, footlight feel for the band. We had used Zip Strips before, but of course they don’t change color, so when the Stagebar came out I wanted to look into that. It worked really well. I like that they were bright.” Integrity Lighting out of Tulsa, Oklahoma supplied the lighting for the tour.
Slaughter feels that adding the amber and white LEDs helps the color mixing on the Stagebars. “It is amazing. I could get a straight amber or CTO out of it with no problem at all. For the colder songs, you can bring up a no color and it is very, very cold. We are using the Jands Vista, so you literally have the color palette there, we could just go in and touch any color that we wanted and it would come up. The color mixing is a big feature that everybody talks about. Even when we go into churches, they ask, ‘How is the amber and white?’ The Church LDs want to know our experience with them. We show it off for them. It is a big hit for Martin.”
When asked if there was anything that he would like to see improved or changed in the future, Slaughter hasn’t run into a lot that he would change. “We had no real problems with them. One or two would get stuck and you would have to hard reset it. When it would reset, it would strobe briefly and flash white. It was a little distracting,” he contends.
Slaughter concludes: “For what it does; we had 24 and they really fill the stage well, even in arenas. I would even bring these out with a downstage truss to fill in gaps. The floor stand mechanism was great; it made it easy to focus the units. We really relied on the unit; it was an important part of the show. We couldn’t have done it without the Stagebars. I was impressed with them; they really saved the day for us.”
If you want to add LED lighting to your productions, it would be worth your time to get a demonstration on the Martin Stagebar 54 LED luminaire and decide if it is right for you.
Michael S. Eddy writes about design and technology. He can be reached at mseddy2900@hotmail.com. Email Michael S.
