LED Source Four

[JChenault]

First look ETC Led S-4

I had the opportunity to take a look at the new ETC Source 4 LED Lustr. Thought it might be interesting to share.

At the Hemsley portfolio review, ETC brought in an LED unit, and an incandescent S-4. They compared them by focusing the units on a white wall about 35 to 40 feet from the fixture. Each unit had a 36 degree HiDef lens tube. The incandescent unit was lamped with a 575 watt Extended life ( IE dim) lamp. In brief - a very impressive fixture for a lot of applications. Here's what I saw and heard.

Brightness. First of all, the ETC party line seems to be that comparing to a 575 watt extended life lamp is a reasonable approach since the extended life lamp is the one most frequently used. Not sure where they got that data, but I feel a ControlBooth Poll coming on.

With all LED's on ( which give a reasonable approximation of white light ) the LED unit is about half as bright as the ungelled incandescent fixture. With intense colors, it was substantially brighter. I did not have the chance to dial in pastel colors and compare to the same gel in the incandescent fixture. My gut feeling is that the crossover point for intensity would be any gel that transmits about 25%. I am sure this number varies with the hue of the color.

The dimming curve is wonderful. They use a single channel, but ( according to the rep) internally convert the 8 bit value from the console to a 14 bit internal value based on rate of change over four cycles. We did some 30 second fades and I did not see any stepiness in the curve at all.


The beam is very precise. It shutters quite sharply, and has no appreciable color fringing. Let me say that again as it is important. No appreciable color fringing on a shutter cut. We put in a gobo, and had some slight color fringing when the gobo as we played with the focus. They have a special frost to put in the gate with the gobo to reduce this. The frost helped a little, but there was still a touch. Let me be clear though, I had to look hard to see any color fringing. If you had not known it was a color LED unit and had been looking for it I don't think you would have seen anything. Using the 'All leds on' color, there was about as much color fringing as you would get with an incandescent unit as it moves out of focus.

Shadows cast by the beam are very natural. We compared by setting up the LED and incandescent unit side by side, projected them to the same circle on the wall, and shuttering so that the right side of the beam was incandescent only, and the left side was LED only. We stood in front of the beam with our hands out to see what kind of shadows we got. The sharpness of the shadow was a bit better with the LED unit than the incandescent unit. If you looked hard you might be able to see a tinge of color fringing - but again you would have to look very hard. This fringing was only apparent when we were close to the fixture. IE with a 35 foot throw, when we were within 15 feet of the fixture. I would say there is no appreciable color fringing with shadows.

The LED unit is not a completely even field. It is hotter in the center and drops off a bit to the edges. This is be design so you can blend adjacent units. There is no way, however, to adjust the field of the LED's. IE no knobs on the back to even or spot the field of light. It does what it does.

The unit does have a fan. I could tell by putting my ear to the back of the fixture and I could feel the air flow. I COULD HEAR NOTHING!! This is the first silent cooling fan I have ever experienced, and that amazed me.

If you get a chance to see the unit, remove the lens tube. You get a pattern of the LED emitters projected on the wall in sharp focus. Pretty cool.

The price that was mentioned was $2500.


My takeaway - very interesting unit. At this point I don't think that it is bright enough for general use, but it does make sense for many applications. I was impressed.

 

[derekleffew]

Re: First look ETC Led S-4

...Brightness. First of all, the ETC party line seems to be that comparing to a 575 watt extended life lamp is a reasonable approach since the extended life lamp is the one most frequently used. Not sure where they got that data, but I feel a ControlBooth Poll coming on.

I don't think we've ever done an official poll, but many had strong opinions in this thread: http://www.controlbooth.com/forums/...res-long-life-lamps-vs-high-output-lamps.html . Summary: Professionals use the brightest lamp available; educational institutions should go for long life; rental companies use whatever their clients will bear. New poll here: http://www.controlbooth.com/forums/lighting-electrics/28081-poll-what-kind-hpl-lamp-do-you-use.html .

...The dimming curve is wonderful. They use a single channel, but (according to the rep) internally convert the 8 bit value from the console to a 14 bit internal value based on rate of change over four cycles. We did some 30 second fades and I did not see any stepiness in the curve at all.

Did they demonstrate the amber-drift (red shift) menu option? I think that is one of the best features of the Desire line.

...We put in a gobo, and had some slight color fringing when the gobo as we played with the focus. They have a special frost to put in the gate with the gobo to reduce this. The frost helped a little, but there was still a touch. ...
The LED unit is not a completely even field. It is hotter in the center and drops off a bit to the edges. This is by design, so you can blend adjacent units. ...

I'm not at all happy to hear this. Unless I choose otherwise, I want my profile spotlights to be absolutely even across the field, and to obtain a razor sharp edge. If I want blending, I'll add my own R132 or ETC's "soft wash diffuser" or (last resort) run the barrel.

(DL speaking Pure speculation on my part:
The Soft Focus Diffuser (gobo slot): to prevent undesirable X7 color fringing when patterns are used.
The Smooth Wash Diffuser (color frame): to soften the edge much like we currently use R114/119/132. By simulating a point source, the LED S4 softens even less good than the HPL model, when "running the barrel."

Was the above clarified any? It seems to me that for gobo projection, particularly text and logos, a peaky field, as well as color fringing, would be quite undesirable. The gobo slot diffuser did nothing to even the beam? Those of us who remember the peak/cosine debate of the 1980s (black axial Strand-Century ERS's) eventually just gave up, resigning ourselves to "just set everything for cosine, and stop worrying about it." I don't know anyone who purposefully peaks an ellipsoidal during bench focus.

Thanks for the in-depth review, JChenault. Can you tell us when we might expect the bazillion iterations of fixture personality profiles for the GAM Plexus for these fixtures? I wonder if one could just copy the profiles for the Desire D40 and D60?
EDIT: Oh wait, that won't work, as I believe they've substituted a white circuit for the orange in the X7.
And why does no one ever mention Metamerism when talking about Selador fixtures?

 

[Techfiend]

Re: First look ETC Led S-4

You can run the Lusters with the D60 profile, same LED colors. All three versions are very impressive as far as LED technology goes when comparing it to conventional source fours. Yes, they are dimmer than a conventional, but for where LEDs were a year ago, quite impressive.

From the experience I had with all three versions, the beams are much more even than a conventional with almost no beam/field angle, because of this the overlap is noticeably brighter. The frost inserts which we were calling frost gobos don't seem to have much, if any effect, in the Tungsten and Daylight fixtures. I believe this is because the LED array is all one color, however in the Lusters, it does help to even the array and blend the colors preventing multiple shadows.

Didn't notice the "Amber shift" option on the fixture menu, and when compared side to side with a standard source four, the S4LED didn't seem to shift. I will investigate and see if it is possible on the lusters' menu.

 

[Wood4321]

Does anyone know what the downside of using non-edlt lenses is? I am contemplating 8 of these for an effect color wash, but would like to avoid buying lenses if at all possible?

 

[chausman]

Does anyone know what the downside of using non-edlt lenses is? I am contemplating 8 of these for an effect color wash, but would like to avoid buying lenses if at all possible?

My guess is that it will cut down on the light output as the EDLTs have higher quality glass then the non-EDLTs.

Didn't notice the "Amber shift" option on the fixture menu, and when compared side to side with a standard source four, the S4LED didn't seem to shift. I will investigate and see if it is possible on the lusters' menu.

They call it "Red-shift" in the menus.

 

[derekleffew]

They call it "Red-shift" in the menus.

From the preliminary cut-sheet cited earlier:

HSI with ‘Plus 7’ Enabled:
Theatrical lighting:
Duplicates the color and dimming behavior of tungsten stage lighting fixtures
• Incandescent dimming curve
• Regulated output for color consistency
• 3200K white point setting

From the Desire manual:

Red Shift
The fixture automatically changes its apparent White Point, or color temperature, as a
function of overall intensity. This allows the fixture to match its dimming performance to that
of a conventional tungsten lamp. Red shift works with both white-light and colored-light
output settings. It is also known as amber-drift and tungsten shift. Red shift is available only
in the HSI and RGB profiles. It is not available on Studio Daylight and Studio Tungsten
fixtures.
Step 1: On the LED Settings menu, scroll to Red Shift.
Figure-3.13 Selecting Red Shift on the LED Settings Menu.
Step 2: With Red Shift selected, press [Enter] to toggle between Disable and Enable.
Step 3: Press [Up] or [Down] to commit the option.

-----

... The LED unit is not a completely even field. It is hotter in the center and drops off a bit to the edges. This is by design so you can blend adjacent units. ...

...From the experience I had with all three versions, the beams are much more even than a conventional with almost no beam/field angle, because of this the overlap is noticeably brighter. ...

Two opposing impressions? Perhaps a third party who has evaluated the unit can weigh in?

Techfiend, I heard a rumor (too late BTW) that your university was lent units to use for an actual show. Care to tell us more? (Or must we wait for the inevitable magazine article/propaganda?)

 

[Techfiend]

I will check the Red Shift option, didn't notice it for before, but then again I wasn't looking.

I believe I can talk about it now that ETC has officially released the S4LED... I'll just give a general run down.

We did use all three variations in a show (Yes Derek, it is too late to see). The Tungsten and and Daylight where used as two front light systems with a third being a standard S4. The Lusters were used as a top gobo. The Tungsten is very similar to a standard S4 but it is a bit warmer of a color temperature. The Daylight is very.... white, more like an arc lamp, but thats to be expected out of a 5600K lamp/LED, I suppose. The Lusters have a wide range of colors with x7, and +7 enabled. I will say that the color picker via gel manufacturer is a bit off, but again that might be expected... Not sure if it was because we were using the D60 profile or not.

RDM is available on the fixtures and is fairly straight forward, allowing you to change any of the fixture settings from the board.

I will agree with JChenault, that the dimming is not steppy like normal LEDs, we were in 'incandescent' fade mode.

The fixtures operate like a normal S4, shutters, gobo, accessory slot, assembly rotation.

I'll see what I can do about pictures...

 

[jmcgregor]

Check out the pictures below for something unexpected. I thought the phenomenon was kind of interesting/cool when I saw the S4 Lustre+ LED units at the factory a few weeks ago... Even though you see the image of the individual emitters on the front lens, you do not see any of this in the field. As mentioned earlier - it's very very impressive, shutter cuts and gobos are sharp. The fixtures are everything you expect from a conventional S4 (minus the equivalent brightness in white - as discussed above...)


Just kind of cool. Thought I'd share. I'm very excited about this product and its potential as discussed previously. It really gives us all another (very powerful) tool for the toolbox.

 

[JChenault]

From the preliminary cut-sheet cited earlier:


Two opposing impressions? Perhaps a third party who has evaluated the unit can weigh

My impression is that etc has attempted to design a happy medium between flat and peaky. If you glance at the field it looks pretty flat. If you look closely you can see a bit of drop off. Sorry if I was not precise

 

[Wood4321]

Twenty Five Hundred Dollars!? No freakin' way is this going to catch on with anyone other than the most highest of high end theatres and rental houses. Twenty grand for 8 lights? Sorry, but a lunar space station will catch on first...

Remember, this is list price.
Your price may be lower,depending on your relationship with your etc dealer.

 

[derekleffew]

Re: First look ETC Led S-4

...Brightness. First of all, the ETC party line seems to be that comparing to a 575 watt extended life lamp is a reasonable approach since the extended life lamp is the one most frequently used. Not sure where they got that data, but I feel a ControlBooth Poll coming on. ...

Surprisingly (to me anyway), the "ETC party line" appears to be correct, at least according to one lamp manufacturer:

...The biggest sellers at the moment are the 575W 115V/X (Long life). They by a very slight margin edge out the regular 575W 115V HPLs ...

Even if not necessarily reflected in our very unscientific poll: http://www.controlbooth.com/forums/lighting-electrics/28081-poll-what-kind-hpl-lamp-do-you-use.html .

 

[bishopthomas]

Remember, this is list price.
Your price may be lower,depending on your relationship with your etc dealer.

Yes, I understand, and also know how to (generally) extrapolate dealer cost from that. Even at cost I won't be buying them any time soon.

 

[Wood4321]

Fair enough,
I just thought it was worth mentioning for those folks that don't realize that list price is almost never paid by anyone...

 

[rochem]

So I saw ETC's presentation on the LED Source Four today at USITT, and spent a pretty long time talking with some of the reps about the product. Mostly, I can just reinforce and back up what others have said. The fixture is pretty darn close to matching a conventional Source Four, and I can confidently say that anyone who was not closely looking for differences would not notice anything at all. However, seen side by side, there is definitely a small visual difference, but so small that ETC's videos or the photos I tried to take can't really show it. The color mixing units are superb, but they use the same color engine as the Desire series, so this isn't really anything new. ETC themselves will admit that the 7-color LED system isn't a perfect imitation of a full-spectrum tungsten source, but for the most part it is extremely close and only noticeable under the most extreme circumstances. The dimming curve is very smooth, but the very low end of the dimming curve is still a little bit off. The biggest thing that annoyed me about the fixture was the completely flat field - after using tungsten source fours for so long, the totally flat field actually looks unusual and unnatural, and that was the biggest thing I noticed that made it stand out from the conventional S4. It's still bothering me that they haven't yet showed the 3200K LED Source Four with a gel in front of it - tomorrow I'm going to try to push them to drop gels in front of the conventional and LED units to compare them.

However, I believe ETC deserved a huge standing ovation for the direction that they're going with the marketing for this product. Over and over and over again, the ETC reps were the first ones to say that the Tungsten Source Four was NOT dead, and they did not envision the LED Source Four ever completely replacing the conventional. Instead of marketing it as an alternative to the Source Four, they're marketing it more as just another tool in the toolbox. As part of their new "layers of light" slogan, the reps talked about how the advent of moving lights changed many things in the industry, but even more than 30 years after the moving light was introduced, even the largest lighting rigs still have many incandescent ERS, PAR, and fresnel units. In fact, more than one rep I spoke to came right out and said that "the Source Four LED is not bright enough to replace conventional units in many applications." Instead of advocating replacing your entire rig, they offered a different approach. Instead of having three or four colors of backlight, maybe just have one conventional S4 in No Color, and an LED product next to it to tone the stage and allow you to have virtually unlimited downlight colors without needing 3+ units on the pipe. They're really marketing it as a whole new type of instrument that you would choose for specific applications, much like choosing an ERS versus a Fresnel, and I think it's working.

(Un)fortunately, the product is actually so good that any of the "problems" or issues are such that they can't really be noticed in a photo, and none of the photos I took really showed anything of note. That said, if anyone has any questions or things they want me to look into, I'm more than happy to do so.

 

[MNicolai]

There are interesting bullet points from the spec document that we certainly won't want to overlook:

+ The fixture shall be capable of copying all performance settings to other fixtures of the same type via a 5 pin XLR DMX cable.

+ The fixture shall be compatible with the ANSI RDM E1.20 standard
a. All fixture functions shall accessible via RDM protocol for modification from suitably equipped control console
b. Temperature sensors within the luminaire shall be viewable in real time via RDM

+ The light beam should have a 2-to-1 center-to-edge drop-off ratio.

+ Available options shall include but not be limited to:
a. Bare-end, Stage-Pin or Twist-lock type-equipped power leads
b. PowerCon to PowerCon cables for fixture power linking
c. Smooth Wash Diffuser for overlapping beams of light from multiple fixtures

I'm going to take a wild guess and say that the Smooth Wave Diffuser is what you use when you don't care for the flat field.

As someone who's had a 40-fixture Selador rig in the air for the last 9 months, I also want to point out how much I love that there will be an ability to copy settings across all fixtures on a DMX universe via one fell swoop. You have no idea how tedious it can be when you want to switch between RGB and Direct mode, or switch between an Incandescent and Quick dimming curve. I can waste a full day with our Desires if I want to spend some time trying the different modes out, and there are certain reasons I need to switch between dimming curves for particular events -- things I can't do with the Desires in anything but the Quick dimming curve mode. Being able to change one fixture and then propagate that change to all would be super-handy.

Of course, the two reasons that's a pain for me presently is because 1) we use a non-RDM console on 2) a non-RDM compliant network. In a different venue I work at with our Congo consoles, that will soon be less of a hassle because according to the community forums, ETC is working on RDM capabilities for Congo consoles, and that theatre has a Net3 RDM-compliant network. With RDM, it should be pretty easy to switch the settings across all fixtures via the console. Here, without an RDM-compatible lighting system, we're stuck with having to locate, plug-in, and manually-switch all fixtures in the system at one at a time.

For those venues that don't plan on becoming RDM-compliant anytime soon, the copy/paste feature will save a whole lotta headaches.

One of the bullet points not included in the spec document that I presume ETC will be bringing over from the Desire series is the self-terminating DMX feature. To my knowledge, ETC remains the only lighting manufacturer to incorporate this into their fixture design. It's a small feature most people overlook, but only until they terminate a DMX run to a bunch of Desire fixtures and find out the hard way that unnecessarily terminating that DMX run causes everything to go haywire.

 

[MNicolai]

For the life of me I cannot remember his name, but somebody should come up with an award to give to ETC's optical engineer.

Remember 2-3 years ago when we'd bicker here on CB about how a Source Four LED retrofit kit wasn't possible because of the physics of a point-source in an ERS fixture? Now we take it as given that it's possible. Even 2-3 years ago, we agreed that if anyone was going to come up with a way to make a retrofit kit -- not just an LED ERS fixture, but something that could retrofit onto an existing Source Four -- that the company who would be able to do it if any could would be ETC.

It's a team effort over there and to give credit to just one or two people would be unfair, but a small handful of scientifically brilliant minds in optics, electronics, and lighting have collaborated to make something pretty amazing -- something that just a couple years ago a lot of us on CB were almost certain wasn't possible (though we hoped that it was). The LED Source Four isn't the given that a lot of us are taking it for, it's the product of some fascinating science and hard work.

I've probably been drinking a little too much kool-aid, but remember that this is [one of] the most significant overhauls of optics in an ERS fixture since the ERS was invented in 1923.

 

[Malabaristo]

... It's a small feature most people overlook, but only until they terminate a DMX run to a bunch of Desire fixtures and find out the hard way that unnecessarily terminating that DMX run causes everything to go haywire.

This sounds like you're suggesting that plugging in a termination plug to a self-terminated fixture is a bad thing, but it really shouldn't be. The way self-termination works is through a switch in the female XLR connector that opens when a plug is inserted. Unless something is physically damaged, there's no risk of double-termination.

Back on topic: this is a really exciting product that I could make very good use of.... if the high school program I work with regularly had a budget larger than it's list price.

 

[dkinzer]

I am one of the designers of the optics for the Source 4 LED.
First, thank you for the constructive comments.
Second, I'd like to clear up some muddy waters.
1) The field, while it may look flat, has a roughly 2:1 falloff. If you blend two beam with hard edges, there will be a bright stripe where the beams overlap. Placing a diffuser (included) in the gobo slot and soft focussing the lens tube improves the blending.
2) The output of a Lustr+ (color) unit is 4200 field lumens with a 26deg EDLT lens tube. This is for a cold fixture with all channels turned on full, and we (ETC) stand behind that number. Complete photometric data will be up on our website soon.
3) The comparison lumen measurements referred to by derekleffew were taken by myself and another optical engineer in a side room at PLASA last fall. We used a high-quality photometric camera and repeated the measurements for all who visitors who wanted to see. We asked Prism to let us measure a RevEAL profile, but were turned down.

 

[STEVETERRY]

Dave, thanks for illuminating the issue with engineering facts.

ST

 

[Wood4321]

I got my first demo of this fixture yesterday.
Overall a very impressive fixture! By far the best looking LED ellipsoidal I have seen.
I did test it without the EDLT lens, and it looked great, right up until I softened the focus, or put a gobo into it.
If you are willing to run it with a hard edge, I think you would be alright with a non-edlt lens.

Output was very impressive when compared against a 575 watt sea changer unit.
In pale colors (Yellow especially) the sea changer was a bit brighter, however in heavily saturated colors, (especially Blue) the LED unit was quite a bit brighter.
Overall an incredible too, and the price point was better than acceptable IMHO.