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Are LED pars bright enough to actually be usefull?

Discussion in 'Lighting and Electrics' started by Mike944, Apr 2, 2007.

  1. Mike944

    Mike944 Member

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    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?
     
  2. soundlight

    soundlight Well-Known Member

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    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?
     
  3. JSFox

    JSFox Active Member

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    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.
     
  4. proaudio4

    proaudio4 Member

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    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.
     
  5. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    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.
     
  6. proaudio4

    proaudio4 Member

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    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
     
  7. jfitzpat

    jfitzpat Member

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    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
     
  8. Mike944

    Mike944 Member

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    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.
     
  9. Jezza

    Jezza Active Member

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    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.
     
  10. Pie4Weebl

    Pie4Weebl Well-Known Member Fight Leukemia

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

    len Well-Known Member

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    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.
     
    Last edited: Apr 3, 2007
  12. jfitzpat

    jfitzpat Member

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    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
     
  13. stantonsound

    stantonsound Active Member

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    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.
     
  14. SHARYNF

    SHARYNF Well-Known Member

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    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
     
  15. icewolf08

    icewolf08 CBMod CB Mods

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    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?
     
  16. SHARYNF

    SHARYNF Well-Known Member

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    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
     
  17. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    Hey Sharyn, How long of a throw are you getting out of those Weidamarks before they lose their punch?
     
  18. proaudio4

    proaudio4 Member

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    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.
     
  19. SHARYNF

    SHARYNF Well-Known Member

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    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
     
  20. len

    len Well-Known Member

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    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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