LED Stage Light Reviews

We recently examined several LED stage lighting units for a high school black box theatre with a 20’ high grid. The school is determined to have an all LED system, but doesn’t have the budget for top-of-the-line equipment. Our goal was to find a set of lower priced units with reasonable performance. It turned out to be harder than we thought. Here are our reviews:

Altman Pegasus LED Fresnel. This 140W white light LED Fresnel is a winner. The optics are very good, the intensity is great, and the dimming (when controlled via DMX) is very smooth all the way out. This unit uses standard 7.5” accessories, so the school’s existing accessories will fit it. This is one of the more expensive unit we examined, but the performance makes this fixture worth it.

Chauvet Ovation E-910FC. This 270W profile has very high color rendering (due to the Red, Green, Blue, Amber, Lime color mixing) and great intensity.   The down side is that Chauvet’s optics are very poor. Whenever a shutter is used to shape the beam the multiple LEDs produce multiple shadows. This problem was evident for most of the second and third tier manufacturers. Although we didn’t test a template, we have to assume the same problem would occur, making this unit useless as a profile.

Elation Arena PAR Zoom. This 190W PAR has a motorized zoom, which simplifies making slight adjustments to the beam angle. The intensity was good, as was the dimming. The optics, however, were not. Each of the 19 LEDs has very good primary optics, but there is no secondary optic to homogenize the beam. This results in beam irregularities and produces multiple, clear shadows that would be unacceptable to an audience as close to the stage as they are in a black box theatre.

elektraLite 1018 PAR. This 216W PAR suffers from the same problem as the Elation PAR. There is no secondary optic, resulting in an unacceptable multiplicity of shadows.

ETC Source 4WRD Profile. This 155W white light LED profile is also a winner. The optics, intensity, and DMX dimming are all very good. This unit is $200-300 more than the other profiles we reviewed, but like the Altman Pegasus, its performance means that it can be used in the close quarters of black box theatres.

Osram Kreios Fresnel. This 80W white light LED unit has nice optics and an impressive zoom. The dim speed fading down to zero and up from zero is a little fast, but we think that can be managed by adjusting the dimming profile. Unfortunately, at only 80W this unit is too dim to be useful from a hanging height of 20’.

Osram Kreios Profile. Like the Osram Fresnel, this 100W white light LED unit also has nice optics and an impressive zoom. However, as with the Fresnel, it is better suited to smaller venues with lower hanging heights.

We plan on looking at other units, but our current thinking is that the school should have a base inventory of white light LED profiles (Source 4WRD) and Fresnels (Pegasus) that is supplemented with a small number of color changing profiles (ETC ColorSource).

LEDs In Stage Lighting

In a project meeting yesterday a team member said that LED stage lights would save the owner money.  While there are many reasons to include LED lights in a theatre’s equipment inventory, cost savings is not one of them.  We’ve written a white paper, LEDs In Stage Lighting, that includes an economic analysis and simple rate of return.  Get a copy here.

MIT Creates Incandescent Lamp As Efficient as LEDs

Researchers at MIT and Purdue University have demonstrated an incandescent lamp with an efficacy of 6.6 percent, and with a potential efficacy as high as 40 percent. The paper was published in the April issue of Nature Nanotechnology. The demonstration compares favorably to current low efficacy fluorescent and LED lamps, while the upper limit is double the current maximum efficacy for fluorescents and LEDs.

The lamp uses a flat filament, rather than the coil of typical incandescent lamps, that is held between two plates of glass with a coating similar to a dichroic reflector, which the researchers call a photonic crystal. The plates permit visible light to pass through them, but reflect the infrared light back to the filament further heating it and producing more light. This idea has been with us for a while now, with most major lamp manufacturers producing some version of an IR halogen lamp. The main difference is that the new dichroic-like coating is much more efficient than the coatings currently in use and works at a much wider range of wavelengths and angles.

This is great news for those of us who haven’t bought into the idea that LEDs will make everyone happy, make all of our children above average, and help the country win the war. Between the low LPDs of the current versions of Standard 90.1 and other energy conservation codes, and the high efficacy of LEDs, most of us are compelled to use LEDs as the primary light source in many of our projects whether we want to or not. LEDs are great, but they’re not the best design choice for every application. As my students and readers of my book know, I regard energy efficiency as an important consideration in any lighting design, but not the primary goal. My first goal is to understand and deliver the desired look and feel of the space I’m lighting while providing appropriate light levels. My second goal is to explore the possible techniques and technologies that I can use to achieve my first goal. My third goal is to use the most energy efficient option from among the best options.

As a designer whose primary concern is the quality of the living/working/shopping environment I’m helping to create, I want to have as many tools at my disposal as possible, not just LEDs. At this point, it seems that lamp and fixture manufacturers are fully embracing the LED with very little attention paid to other light sources, with the possible exception of the OLED. If this experimental lamp becomes commercialized, we’d be able to use inexpensive, tried-and-true dimming technologies that deliver the performance we want without any of the problems associated with fluorescents and LEDs (flickering, flashing, dimming curves that are too flat or too steep, inability to dim smoothly to 0%, high cost, etc.).

This lamp wouldn’t be a solution for all lighting situations of course, in the same way that the LED isn’t a solution for all situations, but it would allow us to have true incandescent light in any application that called for it without running afoul of energy conservation codes. The best of all possible worlds!