ETC Source Four LED Fixtures

by Justin Lang

ETC Source Four Lustr+
ETC Source Four Lustr+
A close look at the LED version of an industry standard

As the LED craze took over the entertainment industry, one of the most frequently-asked questions was, “When will ETC’s Source Four go LED?”

At ETC’s CUE, a conference for end-users held in the company’s hometown, Middleton, Wisc., in July, 2011, the answer came as CEO Fred Foster took the stage and started talking about color. Lo and behold, what started out looking like the beam of a Source Four fixture began to change color.

That particular Source Four LED prototype was hidden away in the ceiling, but within six months, ETC was ready to introduce its Source Four LED line to the world.

There are now three versions of the Source Four LED: the Daylight, Tungsten and Lustr+. The first two are standard white fixtures, color-corrected for daylight (5600K) or tungsten (3000K). The Lustr + is based on the Selador 7-color mixing system, with red, white, amber, green, cyan, blue and indigo LEDs.

Overall Look and Feel

The original Source Four has long been a “go-to” fixture for the entertainment lighting industry.  It is one of the most-recognizable fixtures on the market, with more than three million built and sold since the fixture’s launch in 1992.

The Source Four LED series of fixtures follows the design and shape of the original fixture. In fact, the front half of the Source Four LED is the exact same body as the original.

Also like the original, all three new Source Four LED fixtures work with any of ETC’s interchangeable lenses, from 5° up to ETC’s 90° barrel. ETC has even adapted the LED engine to fit their 15-30°and 25-50°zoom fixtures. Since the front housing is the same, the Source Four LED accepts all the pattern holders and iris gate accessories, along with the four independent shutters.

The gel holder at the front also accepts the standard 7.5-inch square color frames and any other accessory designed to hang off the front — although, admittedly, that capability might seem a bit redundant with the Lustr’s 7-color mixing system.

The back half of the Source Four LED looks similar to the original design, but a bit larger. It holds the LEDs, fans, power supply and the additional connections needed to control the fixture via DMX. The back half is also where you’ll find a PowerCon in, PowerCon pass-through and 5-pin DMX In and Out.

The “burner assembly” on the LED version is hugely different from the original.  Rather than the typical lamp adjustment knobs, it has been replaced with an LCD screen for configuring, addressing and setting up the fixture.

Despite all its brightness and functionality, the Lustr+ fixture draws just 128W at full intensity.  Since the fixture requires a non-dim circuit to power the fixture, rather than using multiple outlets, you can easily daisy-chain power from fixture to fixture with the PowerCon pass through — up to nine fixtures off of one run.


Built-in Controls

ETC has designed the Lustr+ version to be configurable for use in applications ranging from theatrical settings, making heavy use of the fixture’s seven-color mixing system, or in a TV studio, where the need to control the color temperature or plus- or minus-green settings comes to the fore. Users can simply turn to the fixture’s five on-board “Quick Setups” for DMX control — including General (with 10 DMX channels), Stage (6 or 15 channels), XT Arch (6 channels), High Impact (6 channels) and Studio (6 channels).

Users will find local control for testing and diagnostics also part of the built-in, on-board controls.  They can also set up the fixture to run locally, without DMX, via the built-in and re-programmable presets. The system even lets users check incoming DMX signals.

What About Output?

Ask ETC whether the new Source Four LED series — the Lustr+, Daylight and Tungsten fixtures — are designed to replace the fixture we all know and love, and the answer is “No.”

I would have to agree with them on this point.  While the Source Four LED Lustr+ has some punch to it, especially in saturated colors, the output is still behind what we have come to expect out of a Source Four.

Setting up the Lustr+ fixture at 25 feet with a 19° lens at full intensity, the center of the beam was reading 120 footcandles, with a drop-off to 70 footcandles at the edge.  Compared to a 575W tungsten Source Four, that represents 10 to 15 percent less output.

In a side-by-side comparison of a 575W tungsten and the Lustr+, it is easy to distinguish between the two fixtures.  The Lustr+ just wasn’t as bright — although it did offer a more even beam.

When running the Lustr+ without a barrel, I noticed that the fixture’s individual LEDS were clearly visible. Although it’s not an effect that everyone’s going to fall in love with, it remains an interesting option for LDs who want to take an unconventional approach (Source Fours are typically not meant to run without barrels).

Summing Up

All in all, while the Lustr+, the Daylight and Tungsten LED options aren’t intended to replace ETC’s more traditional tungsten fixtures, they would prove a good fit for short-throw applications, and their energy efficiency is a big plus. Rep plots and general wash layouts also stand to benefit from the Lustr+, trimming the need to hang multiple Source Fours with different colors.