Are LED pars bright enough to actually be usefull?

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.
 
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
 
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.
 
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.
 
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.
 
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.
 
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
 
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.
 
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.
 
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.
 
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.
 
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.
 
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.
 
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
 
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.
 
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.
 
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
 
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.
 

Users who are viewing this thread

Back