# Are LED pars bright enough to actually be usefull?



## Mike944 (Apr 2, 2007)

Hey guys.

Planning a show (contemporary dance show) in a venue with basically no available power. Just 15A wall circuits, and i don't know how many (No, i didn't pick the venue!!!)


With low available power, my first thought was LED pars, since they cosume very little power. I've only had a chance to look at one unit 6 months or so ago, and my only memory was it was kind of dim, especially compared to an ETC par (my usual choice) I'd be renting these, so money isn't really part of the picture, unless i'd have to rent significantly more units than i would have normally. My concern is adequate light and lumens / amp efficiency.

Anyone have any experience / suggestions?


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## soundlight (Apr 2, 2007)

Which model would you rent? These units really run the full range of power and brightness. Also, how high is your trim for electrics? Will these only be used for down, back, and side lighting, or also FOH?


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## JSFox (Apr 2, 2007)

In my world dance often calls for fairly bright lighting, though there are exceptions. Just as a rough guess I'd think you'd need 3 - 5 times as many LED instruments (and this is assuming James Thomas PAR's) as you would 1000w instruments. HOWEVER, if the show calls for alot of saturated colors you might be good with fewer - perhaps 1 - 2 times as many LED's. I think you really need to look at the photometrics of the specific LED's you'd be renting for the colors you'd need against the photometrics of standard instruments (accounting for loss via gel/dichroic). Once this is done you need to calc the power draw of the two options. Generally to do an equivalent color level on stage the LEDs will draw less power, but not always.

Also realize that some (most?) LEDs do not dim smoothly so you'd want to verify that before committing.

This is, BTW, from someone who is a huge fan of LEDs.


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## proaudio4 (Apr 2, 2007)

Speaking of which...

Can anyone name one DMX LED PAR can than does not flicker when dimming or adjusting its RGB channels?

I own the Weidamarks and the flicker is horrible while adjusting.
This makes it tough for slow color fades.


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## gafftaper (Apr 2, 2007)

I would look at the Altman LED PAR's. They cost 10 times what the Weidamarks do but they are using color kinetics technology so they are much brighter and have much better electronic technology behind them for better blending than the cheap ones. On the other hand... you can buy 10 Weidamarks for one Altman LED PAR.


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## proaudio4 (Apr 2, 2007)

Thank you
I've heard Altman LED PARS are bright and are known to be decent.

Does anyone own these (or another LED PAR) that can say that they do not flicker when changing RGB levels or fading?

Thanks


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## jfitzpat (Apr 2, 2007)

I've used Chauvet P64 LED pars in a trade show booth and never noticed any flickering. I had them pointing down on some corporate logos made out of metal, doing slow color cycles and periodic fades to black, so it seems like if anything obvious were occuring it would have stood out.

Also, I know that Dave Winters had to use a bunch of LED fixtures because of power restrictions on this 2mex/Look Daggers video (he asked for help making fixture templates for some of them). It is hard to tell from the compressed YouTube image, but the color fades all look very smooth in original (though I can't say that I found the music any more appealing - but I'm old).

I've seen a couple of Weidermarks in use by DJ's, but they were just doing bump and flash so I haven't had a chance to see what you are talking about.

-jjf


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## Mike944 (Apr 2, 2007)

JSFox said:


> ....Just as a rough guess I'd think you'd need 3 - 5 times as many LED instruments (and this is assuming James Thomas PAR's) as you would 1000w instruments. HOWEVER, if the show calls for alot of saturated colors you might be good with fewer - perhaps 1 - 2 times as many LED's. ......... Generally to do an equivalent color level on stage the LEDs will draw less power, but not always............LEDs do not dim smoothly so you'd want to verify that before committing.



Thanks for the comments. Using this many more units would probably erase any reduction in power draw. Looks like the only advantage of these units would be the broad-spectrum color mixing capabilities.

To answer soundlight's question, i don't know what brand my regular supplier has available. It's good to know that there is a significant difference between units. trim is whatever i want, I'm going to be bringing in my own rigging and trusses. I wanted to use them everywhere i can. My key problem is lack of power, and i don't want to rent a show power generator. Too much $$$

I guess i'll have to do more research, but it sounds like they're not all they're cracked up to be.

Thanks everybody.


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## Jezza (Apr 2, 2007)

Don't sell let some of these guys fool you with about the Altman LED SpectraPars. They are GREAT for toplight light, etc. I mean yes, you will never get Source 4 PAR output from an LED fixture of the same size, but the SpectraPars back some serioues punch. One of the issues with the flickering is presented by not using a console that thinks in 256 versus some lower bit multipliex like some DJ boards. I've never had an issue with the SpectraPars or the CK ColorBlasts on a real console. The CK strips are great for lighting a cyc. Even so, I've lit a 20'x18' cyc w/ 6 Chauvet 196 LED PARs. Talk to your rental house about the Spectra Pars or maybe the ColorBlasts.


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## Pie4Weebl (Apr 2, 2007)

Jezza said:


> Don't sell let some of these guys fool you with about the Altman LED SpectraPars. They are GREAT for toplight light, etc. I mean yes, you will never get Source 4 PAR output from an LED fixture of the same size, but the SpectraPars back some serioues punch. One of the issues with the flickering is presented by not using a console that thinks in 256 versus some lower bit multipliex like some DJ boards. I've never had an issue with the SpectraPars or the CK ColorBlasts on a real console. The CK strips are great for lighting a cyc. Even so, I've lit a 20'x18' cyc w/ 6 Chauvet 196 LED PARs. Talk to your rental house about the Spectra Pars or maybe the ColorBlasts.



I have had color blaze fading issues on an Obession II and that certainly is a "real board"


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## len (Apr 3, 2007)

I've used the Coemar ParLite or whatever they're called, and they don't flicker that I've seen. As for power draw, they use .45A at 115v according to the website. So you could get about 26 of them on a 15 amp circuit assuming you allowed a 3 amp buffer and only loaded the circuit to 12 amps. The Thomas PixelPar 90 consumes 135 watts per fixture, which is 8 fixtures (roughly) on 12 amps at 110v.


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## jfitzpat (Apr 3, 2007)

Pie4Weebl said:


> I have had color blaze fading issues on an Obession II and that certainly is a "real board"



Jezza's choice of words might have been poor, but the technical point is a good one. I've done a little research into this and it seems the core issue is LED vs. dimmer/douser response speed. For heat/current reasons, LED fixtures overwhelmingly pulse width modulate to adjust perceived intensity. That is, the LEDs are full on, or off. This makes the fixtures potentially very fast in response to level changes. The fixture's firmware could 'dampen' this, that is, simulate the behavior of a conventional lamp and dimmer, but fast has it's uses too.

Jezza mentions one possible problem, a console that calculates and updates output levels in percentage points, and there are still quite a few theatrical desks that do. The issue is that 0-100 gives you less that half the resolution of 0-255. The other potential problem is data update rate. This can be confusing because there are really two rates, the DMX packet rate and the the DMX data update rate. The first is spec'ed and, generally, a board should try to update as fast as the spec allows because there is no error checking in the stream so you want any transmission bit errors to persist for as short a time as possible. The second rate is how fast the board calculates new data to send, and it is almost always much slower than the 44 Hz (or faster) that the DMX spec allows. 

The reason it is slower is that it is important for it to be relatively steady, so an interval is usually picked which the desk can keep up with worst case, work load wise, and yet is still fast enough to give the illussion of smooth fading to the human eye. With dimmers the lowest acceptable speed is about 10-12 Hz (10 is really pushing it). However, with a more responsive LED fixture, the lowest acceptable speed is probably higher.

I do not know if the ETC desk calculates in percentages, but I do know that it's data update rate is relatively modest. Looking at the 'stair steps' in a Gilderfluke PCMACS recording of one's output, I'd say it was about 14 Hz. This doesn't mean that the board is not 'real' or 'good', but it might explain the discrepency between your experience with Color Kinetics and what we can see the ColorBlaze(s) doing in the video I included above. In that instance I can say, positively, that the controller was using all 8 bits, and the data update rate was 30 Hz.

-jjf


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## stantonsound (Apr 3, 2007)

I recently rented a handful of ColorBlast's, by Color Kinetics, and was pretty happy with them. As long as the ambient room lighting is fairly dim, these work very well. They are a truly professional fixture, unlike many of the other fixtures out there, and there is really no problem with flickering. 

The Color Kinetics rep came and gave another lighting company and I a demo of all of their equipment and we were both very impressed. We used a theatre in town and used everything from cyc lighting units to their new color tiles. Yes, you can light a dance show very will with these LED's. The price on the rental is very affordable as well. I paid $35 per LED fixture and $40 for the control unit. We rented 30 of the colorblasts and then 10 colorblaze's for the cyc. We found it best to light the cyc from both the top and the bottom to get the best wash.

Talking to the rep, there are several new fixtures coming out in the next year and they are getting brighter all of the time. They are even working on a LED powered ellipsoidal fixture. The problem that they are having is that it is currently not possible to get good sharp edges and you can not put a gobo in them. They are working on a design that uses an extra set of lenses that will focus the LED's so they would pass through the gobo much like the light from a standard lamp, and eliminate this problem. Their goal is to be the first to do this, so keep an eye on them.

Imagine that, being able to run an entire show on less than 60 amps...... wouldn't Al Gore be happy.


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## SHARYNF (Apr 3, 2007)

I have not had any problems with the Wiedmark units. I find them especially useful for saturated colors, and also washes. I would recommend using standard pars/fresnels with Gels for warm whites. IMO a combination of a few standard and a balance of led's works well. On occasion I have used them with Martin robocolors or Elation Color units, and this works quite well.

What you have to be careful of and may be the cause of the problem is that for instance with the Wiedmark units, the 4th channel is the dimmer but also the channel to select strobing. IF for instance you put that channel full on, and then use a master fader you will find that you go from full on, to STROBE and then to the dimming, If Instead you place the channel level at the 60 percent level or check you manual and see the dmx level that you need for full on, BEFORE you get to the strobe, you will then find that you don't have the strobing problems. It took a bit to get used to how to set them up for people used to just putting the sliders in full on position, so you wind up with for instance channels 1 2 3 being able to use the full slider, but with channel 4 you have amore restricted area. Once past this , they work great.

Some people have expressed the point that if the audience can see the led's they get confused since the led's are segmented and show the addative colors which can be wierd. Personally I have not had a problem with this but there are some efforts to put an extension on the led par to move a filter out 6 inches or more from the led's so that the filter color matches the color that you are using vs the led's being used to generate the color 

Sharyn


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## icewolf08 (Apr 3, 2007)

SHARYNF said:


> Some people have expressed the point that if the audience can see the led's they get confused since the led's are segmented and show the addative colors which can be wierd. Personally I have not had a problem with this but there are some efforts to put an extension on the led par to move a filter out 6 inches or more from the led's so that the filter color matches the color that you are using vs the led's being used to generate the color



Or you could put a tophat on the end thus preventing the audience from seeing the source. It also saves some poor sap the time used to cut color for a unit that shouldn't have color in it... Besides, if the audience is staring into the lights, what does that say about the show?


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## SHARYNF (Apr 3, 2007)

the comment re the "look" has less to do with a theater application vs a band, were it is more likely that you have a set of pars facing forward for the band.

I agree, and in how i use them Don't have an issue, but wanted to bring up all the points that people have knocked about. Personally I think in combo with Some standard units it makes for an excellent solution. I've done some setups where we have a dozen of the led's and 4 500 watt Fresnel on standard dimmers with some bastard amber gels and it worked out quite well IMO

Sharyn


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## gafftaper (Apr 3, 2007)

Hey Sharyn, How long of a throw are you getting out of those Weidamarks before they lose their punch?


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## proaudio4 (Apr 3, 2007)

I can add my 2 cents regarding the Weidamarks.

I measured 200 LUX peak (FULL RBG) at appox. 10 ft.

The best use would be for painting close objects, wall wash, etc. 

I imagine if you bought 24 or more of these, you could wash a 20'x20' stage
assuming the trim height is less than 20 ft.


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## SHARYNF (Apr 4, 2007)

I'd agree with ProAudio4, trim height under 20 feet. Again, in white or full RBP in my experience is probably their worst case, If in fact you use them for fully saturated red or blue, there in comparison to par with the same saturation, I think they perform pretty well. If you cluster them obviously you can also increase the total lux. Have not done a scientific measurement, but that's my feel

Sharyn


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## len (Apr 4, 2007)

Sharyn, ProAudio4, 

Can you tell me which units you're referring to? I'm considering adding some of their products to my inventory, for wall wash etc., but want to get some user opinions first.

Thanks in advance


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## proaudio4 (Apr 4, 2007)

I was refering to Weidamarks LED PAR 64:
http://www.wiedamark.com/index.asp?PageAction=VIEWPROD&ProdID=2015


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## gafftaper (Apr 4, 2007)

Len I think we are all talking about the Weidamark LED PAR's that got a lot of positive talk due to a shoot out thread over on Prosoundweb.com Several people here have been using them with really positive results. That thread on Pro Sound Web is located here.


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## SHARYNF (Apr 4, 2007)

Exactly, give them a call and ask for Dante (one of the owners), they are very helpful and responsive. Tell him Sharyn from Alaska sent you ;-) They are always working on getting the product improved, 

Sharyn


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## Mike944 (Apr 4, 2007)

So, i contacted my usual supplier, and he said he had a few american DJ units (8 units), just really to experiment with. He wasn't impressed enough to buy any more. He did say that he would buy more, if i was willing to rent them.

I managed to find photometric data for his units so i could compare. http://www.americandj.com/pdffiles/P64-LED-PHOTOMETRICS.pdf Even after accounting for transmission losses through gel media on a conventional instrument, they still loose, big time! I would need hundreds to light even a small show. 

The better quality units seem like they have similar light output. i found an article on the Weidamark website, but the impression i got was the rest look brighter then the Am Dj, because they are narrower beamed. The Weidamark units seem a little better, but not 10x better, which would be about how much i'd need to be practical. 

In my opinion, it sounds like LED technology has a few years left to go, before it becomes practical for this application.

Oh well. I guess i'll have to take a walk through the space, and see if i can "find" some more power for conventional units.


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## len (Apr 4, 2007)

gafftaper said:


> Len I think we are all talking about the Weidamark LED PAR's that got a lot of positive talk due to a shoot out thread over on Prosoundweb.com Several people here have been using them with really positive results. That thread on Pro Sound Web is located here.



Seen their website, and I've read some of the prosound thread. Wiedemark offers several pars, pinspots, and even some other stuff that sort of looks like the panels made by Color Kinetics.


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## proaudio4 (Apr 4, 2007)

Mike944, You're right about that!

The Weidamarks measured about 200LUX (full RGB) at 10ft. That's about 3X more LUX than your AMDJ reference.

Though even at that, 200 LUX at 10 ft, this power is extremely weak.

For example, most 250W MSD wash heads will pump out more than 6000 LUX at 10 ft with a 30 degree beam angle.


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## gafftaper (Apr 4, 2007)

Mike944 said:


> So, i contacted my usual supplier, and he said he had a few american DJ units (8 units), just really to experiment with. He wasn't impressed enough to buy any more. He did say that he would buy more, if i was willing to rent them.
> I managed to find photometric data for his units so i could compare. http://www.americandj.com/pdffiles/P64-LED-PHOTOMETRICS.pdf Even after accounting for transmission losses through gel media on a conventional instrument, they still loose, big time! I would need hundreds to light even a small show.
> The better quality units seem like they have similar light output. i found an article on the Weidamark website, but the impression i got was the rest look brighter then the Am Dj, because they are narrower beamed. The Weidamark units seem a little better, but not 10x better, which would be about how much i'd need to be practical.
> In my opinion, it sounds like LED technology has a few years left to go, before it becomes practical for this application.
> Oh well. I guess i'll have to take a walk through the space, and see if i can "find" some more power for conventional units.



Again the only thing I've seen that is really ready for serious use are the Selador X7-Xtra 3 watt LED strip lights. They kick some serious butt over all the LED PAR options that I've seen. They are the only thing I've seen with the punch to wash a cyc without any concern about how much light everything else on stage is putting out. But you still need top and ground rows of lights for at least 75% of the width of the cyc... so 40 foot cyc is going to need at least 60 feet of strips... at about $1500 a foot (when you include the cost of the spreader lenses) that's way out there in budget.


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## SHARYNF (Apr 4, 2007)

Again depends on the application, if you take a high saturated gel the light transmitted will be far less than the full RGB lux level. In this case, using several of them MIGHT be close to other alternatives. IMO the more saturated the color you need, the better the LED's work. If for instance you wanted to have 3 different gels selected, and you compared 6 led's vs all of which could be set to the same "gel" and compared that to say 1 par with the same saturated gel, the comparison looks more favorable. considering the obvious advantage of being able to alter the color on the fly for all 6 of the led's vs a fixed gel. 

Certainly when led performance goes up several orders of magnitude the decision will be simpler

Sharyn


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## gafftaper (Apr 4, 2007)

SHARYNF said:


> Again depends on the application, if you take a high saturated gel the light transmitted will be far less than the full RGB lux level. In this case, using several of them MIGHT be close to other alternatives. IMO the more saturated the color you need, the better the LED's work. If for instance you wanted to have 3 different gels selected, and you compared 6 led's vs all of which could be set to the same "gel" and compared that to say 1 par with the same saturated gel, the comparison looks more favorable. considering the obvious advantage of being able to alter the color on the fly for all 6 of the led's vs a fixed gel.
> Certainly when led performance goes up several orders of magnitude the decision will be simpler
> Sharyn



You are right on Sharyn about saturated color being the strength of LED's. That's also why it's really hard to get any useful photometric data on LED's. Yeah the lumen output is way lower... but which color are you talking about. Throw some R 382 "Congo Blue" and it's .56% transmission rate in a monster like a Source 4 par and it's going to be hurting to be visible over the rest of the lights in the rig. So if the color can be achieved by the instrument in question (which is a whole other topic)... the LED can really kick butt in the deep saturated colors. 

As far as range of color mixing goes, this again is where the Selador rules. They don't just use RGB they use SEVEN colors of LED's. So the range of colors is much greater. The subtle tones of white are much better. You can mix a 3200 degree white vs. a 5000 degree white. They also go way deeper into the saturated colors than other instruments. But again, there's a big price tag attached.


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## soundlight (Apr 4, 2007)

I made the saturated gel point in another LED topic, and I think that this is the main thing that LED's are good at. Even R41 (salmon, a relatively "light" color in contrast to something like congo blue) only has 24 percent transmittancy.

Throw in some 500W pars or fresnels with R05 or R16 for the warm/neutral pieces, and then use the LED pars for the pieces that require the saturated colors.


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## gafftaper (Apr 4, 2007)

soundlight said:


> I made the saturated gel point in another LED topic, and I think that this is the main thing that LED's are good at. Even R41 (salmon, a relatively "light" color in contrast to something like congo blue) only has 24 percent transmittancy.
> Throw in some 500W pars or fresnels with R05 or R16 for the warm/neutral pieces, and then use the LED pars for the pieces that require the saturated colors.


So it seems that we are agreeing that LED pars are great for color as long as the throw isn't too great. However, you need something else for white. So the idea of just buying a rig of LED's for power consumption purposes has a serious flaw in it if you want anything close to bright white light out of them. So for DJ type operations they are great... even the cheap ones. For concert applications they are good as long as you have some other white light to assist. It's when you get around to fully theatrical applications they get really problematic because you need so much more white light on stage and you either run into too much white light from other instruments washing the LED's out or you can't get enough white light from the LED's to be useful. 

It's a really fascinating topic and I'm looking forward to 5 years from now when they are producing 5 Watt, 10 Watt, or even higher LED's that blow away this whole discussion... Then when we finally get the LED Ellipsoidal we have a whole new revolution to deal with.


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## JSFox (Apr 4, 2007)

From a cost standpoint you also have to keep in mind that conventional instruments require dimmers. So, assuming you need 10 of the Wmark LED instruments to equal 1 conventional and you need 3 colors then 10 of the Wmark LED's will replace 3 conventionals plus 3 dimmers plus 3 10 amp cabling. Reality though is that I don't think 10 Wmark LED's will give you the same result as one conventional except for very saturated colors (which for dance you might have).

For conventional theatre colors you're struggling a bit more since most of the LED's can't produce things like special lavendar, etc.


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## BillESC (Apr 4, 2007)

Mike,

Let me know how many Altman Spectra Pars you might need, 

They only consume 50w each.


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## Mike944 (Apr 5, 2007)

gafftaper said:


> You are right on Sharyn about saturated color being the strength of LED's. That's also why it's really hard to get any useful photometric data on LED's. Yeah the lumen output is way lower... but which color are you talking about. Throw some R 382 "Congo Blue" and it's .56% transmission rate in a monster like a Source 4 par and it's going to be hurting to be visible over the rest of the lights in the rig. So if the color can be achieved by the instrument in question (which is a whole other topic)... the LED can really kick butt in the deep saturated colors.
> As far as range of color mixing goes, this again is where the Selador rules. They don't just use RGB they use SEVEN colors of LED's. So the range of colors is much greater. The subtle tones of white are much better. You can mix a 3200 degree white vs. a 5000 degree white. They also go way deeper into the saturated colors than other instruments. But again, there's a big price tag attached.



Even when you account for deep gels, the LED units still loose. Their power output goes way down when you're only running some of the LED's. Again, referencing the AMDJ units here (which appear to be inferrior), the lux output goes down to 7% when just the blues are on compared to "white" light. Are you factoring that in? the LED units don't stay at the same intensity throughout the color spectrum, so there are significant losses here too.

Now, those altman spectra pars look like they'ge got some punch. I'm sure they're a big punch in the wallet too.


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## gafftaper (Apr 5, 2007)

Yeah I saw the AMDJ units at a local music store. The demo room was basically dark and the unit was mounted less than 15 feet from the wall and it could barely cover a 5 foot circle. It was pitiful. LED's are still clearly a you get what you pay for item... I think the Altmans are over $1000 each... Bill care to share a ballpark price? 

On the other hand... years of use, no gels or lamps to change, lower electric bill... one instrument can replace multiples in the rig... they will pay for themselves eventually if you've got the money to afford them upfront.


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## SHARYNF (Apr 5, 2007)

certainly the led's are not for everything, and certainly are not practical for the only source of lighting. I guess if you go back to the original question, are they bright enough to be useful, the answer is it depends on what you want them to do. The overall advantage is that they are being somewhat successful more on the band/dj side of things or HOW or architecture use, but they are driving the prices down, and volume up so I think that over time we will see multiple generations that will start to make them more and more acceptable in more traditional stage

Sharyn


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## soundlight (Apr 5, 2007)

gafftaper said:


> It's a really fascinating topic and I'm looking forward to 5 years from now when they are producing 5 Watt, 10 Watt, or even higher LED's that blow away this whole discussion... Then when we finally get the LED Ellipsoidal we have a whole new revolution to deal with.



10W LED's are already being produced. They're super-insanely expensive though, and 3W luxeons can still compete with them because of the efficiency and reflector and such. So when Luxeon finally gets around to making 10W units...that will be the day, my friends, that will be the day!! It'll be a 21 LED (seven color) fixture, that consumes 210W and has the lighting punch of 3 500W fresnels with low saturation gels, no problem. That's what I see as the future of color washes.


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## proaudio4 (Apr 6, 2007)

After reading Jfitzpat's post regarding refresh rate, I decided to try a few experiments.

I'm using the ENTTEC DMX USB PRO interface. 

The flickering happens with my LED lights. Both the Weidamark LED pars and the Chauvet panels flicker.
The flickering occurs when any one of the LED control channels (RGB, and dimmer) are set to less than 100% full on. When the channels are full on, there is no flicker.


To check for flicker, the following tests were set with the RGB levels set to about 25%. Only one Weidamark LED PAR is connected to the ENTTEC and terminated. Here's what I've discovered:

If I set an LED PAR to channel 69
and limit the amount of transmit channels to 73 (4 channel light), it flickers about once every 2 seconds. Annoying.

Now, with the LED PAR light still set to channel 69, and the amount of transmit channels is set to 510, it blinks rapidly about every 250ms. Very annoying (This is how it has been setup with my other fixtures)

Now, check this out:

If I set the LED PAR to receive on channel 1 and set the amount of channels to transmit to 510, there is some small level of flickering, but is is better. Hmmm, lower channel assignment the LEDs have less flicker.

Now, if I leave the LED PAR set to channel 1 and set the amount of channels to transmit to 5, there is NO flicker! At least none that I could see.

So, it appears for my LED fixtures (both the Weidamark and Chauvet) the best situation is to have very low DMX channel assignements AND to transmit only the amount of channels needed.
It also appears the less channels transmitted, the less flicker.

This leaves me with the following questions:

1. This appears to be DMX refresh rate issue with the Enttec USB Pro widget. How can I adjust this rate with the Enttec USB PRO?

2. Does the refresh rate need to be higher for LEDs opposed to regular lamps? I believe that's what Jfitzpat was suggesting

3. How do I overcome this issue, especially when using a lot of fixtures and channels?

Please help a brother out.


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## SHARYNF (Apr 6, 2007)

HMM you have pointed out an implimentation problem with some of the LED dmx controllers, that I found out but did not see the link to your problem. I noticed that if the dmx signal is removed, instead of the instrument staying at the same level, in fact the instrument goes completely dark. SO if your refresh rate for some reason drops below the threshold for the dmx implimented on the led, you would see a flicker.

Someone else might be more familiar with your system, but I do think you have found the cause.

Sharyn


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## BenFranske (Apr 6, 2007)

That seems to indicate that the fixture needs constant DMX data to stay on. The more channels you add to the uiniverse (either explicitly or by putting the LED fixtures higher up on the list) the further apart the DMX signaling is which is creating the flicker. This is a poor design problem, fixtures should hold the last received setting in memory so if a cable is kicked out you don't loose light and because it prevents flickering in situations like these.


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## soundlight (Apr 6, 2007)

Dr. DMX (good ol' doug fleenor) should make a box that does this. It would basically up the refresh rate to the maximum allowed by DMX on all channels by holding the last value when there wasn't a signal. It would be a good investment for some of the midrange boards that might do this with LED's.


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## proaudio4 (Apr 6, 2007)

Thank you to all who just posted!

It seems odd I'm the only one complaining about this?
There are quite a few Wiedamark PAR 64 users.
Also, the Chauvet ColorBar panels do the same thing.

It appears to be the Enttec DMX USB PRO combo with these LED lights.
I have no issues with my regular MSD bulb lights.

Since I have not worked with the DMX protocol and programming, I'm wondering if some of it is the message sent from the user DMX software program to establish frame rate.

I believe once you send this message, the frame rate stays constant until the next update. It appears the DMX USB PRO is working correcty.
You can set your light to a scene and stop the software and the internal buffer in the DMX USB PRO maintains the condition.


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## proaudio4 (Apr 6, 2007)

Yes Soundlight.

So my guess would be that high end LED units do not display this issue with my Enttec widget?

So this issue seems like a design flaw with PWM duty cyle for LEDs in conjunction with DMX frame rate used. Is this a correct assumption?

Man, I wish I had some different LED lights to try.


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## proaudio4 (Apr 7, 2007)

Well,
Enttec sent me a firmware change to accomadate the LED flicker problem.

The good news is, the firmware change I uploaded for the Enttec DMX USB PRO works as a "band-aid" for the flicker problem with these "cheaper" LED units. He gave me a "special" firmware update to slow down the DMX by increasing the interslot time. By default the USB PRO sends DMX at the maximum speed.

I have not really noticed a performance hit.

Enntec mentioned "they get a number of similar problems on a regular basis and up to now it has always been non compliant DMX512 lights ... 
Each non compliant light reacts in it's own strange way."

I'm real happy to see these lights dim without driving me freaking nuts flickering!
Too bad it's a band-aid approach, but I can live with that.

I'd like to get my hands on some of the expensive LED pars and panels to see if they have this issue.
I heard they do not.


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## DarSax (Apr 7, 2007)

Burning question: Why have they not made fixtures with built-in dimmers yet? The closest you can get is a back-pak, but I'd think a PAR can with individual built in dimmmer would find quite a market on the portable, small DJ market?

(semhijack?)


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## soundlight (Apr 7, 2007)

It makes alot more sense to have seperate dimmers for parcans because of the heat at the back of a PARcan. Also, putting dimmers in groups of four or eight or twelve is much more economical for the end user, because they can share a chassis, power inputs, main fuse, etc.


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## lighttechie5948 (Apr 7, 2007)

Also you have to keep in mind the colors you want to use. The L.E.D.s are great but using a combination of RGB you can only get a very, very "crudy" amber/yellow.

It would be great (if there isn't one already now) if a company would make a L.E.D. par that did RGYB. If there is please respond.


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## soundlight (Apr 7, 2007)

Even better - Selador makes 7 color mixing LED fixtures. You can make just about any color temperature white that you want, and have a huge palette or rich colors to use. The downside, of course, is that they are very, very expensive. But, if you consider the trade-off in electrical consumption, lamp replacements, and heat output, they're really worth it.

This picture says it all about Selador's vast improvements to the RGB system. Look at how much more of the spectrum it covers because of the added 4 colors!


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## lighttechie5948 (Apr 8, 2007)

wow!!!!!!!!


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## soundlight (Apr 8, 2007)

lighttechie5948 said:


> wow!!!!!!!!



That's the general first-time reaction to Selador. Now if the color spectrum possible has put you in to shock because you have suddenly realized what this means for LED technology, we may need to send someone over to help you. Be careful, Seladors have a very high initial WOW factor, higher than some people are capable of containing. Repeated exposure to this new technology allows you to become less likely of going in to shock upon seeing the color spectrum. Extensive exposure to the Selador Color Chart may lead some peoples' computers to shut down because of extensive drooling over the keyboard, while others may try to buy one online, only to realize later, when their credit card statement comes, that buying a Selador is not that great of a thing to do when you were trying to just hold out until the next rent was due.


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## BobMirage (Apr 8, 2007)

Not for this use. You have to consider the amount of space that needs to be lit and to what intensity. Decent LED's have a very tight beam. The few that don't, won't be bright enough. 
You're not limited to LEDs if you have a few seperate wall outlets.
Just don't use old Q1000's. The 575's are about as bright and ~1/2 the power.
Almost all wall outlets are 20 amps. Take a better look at your available power. Can you run power from another room, back of house or tie-in to the main power?
All of this can be sorted-out by hiring someone through your light rental shop or asking the venue if they know someone with lights. It's well worth it.
[email protected]


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## JSFox (Apr 19, 2007)

Just a note that throughout much of the country most duplex recepts are 15a, not 20a. On this page (http://www.nooutage.com/nema_configurations.htm) you can see the configuration difference (5-15R vs 5-20R) that will allow you to tell. Also, just because you see 5 duplex recepts doesn't mean you have 5 circuits as you may have multiple recepts sharing circuits. 

Nothing like being assured that some place has 7 20a circuits only to arrive and find out that they have 7 15a recepts, but only 2 circuits (EG, for a total of 30a).


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