LED Pars

[Guest lightnix]

Warm-white leds is beeing made to, but only in high-power variants...

That's not quite true, warm white LEDs are available in standard 5mm (and presumably 3mm) LEDs, although you are correct in saying they are not as bright as regular (cool) white LEDs.

[peter]

That's not quite true, warm white LEDs are available in standard 5mm (and presumably 3mm) LEDs, although you are correct in saying they are not as bright as regular (cool) white LEDs.

 

Not quite as bright, or not as perceptively bright? Obviously the cooler the source (CT wise), the brighter it will be percieved to be, by the human eye. I'd be interested as to whether the source is actually producing just as much light?

[Dale]

Why can a white LED not be made?

[Guest lightnix]

Not quite as bright, or not as perceptively bright? Obviously the cooler the source (CT wise), the brighter it will be percieved to be, by the human eye. I'd be interested as to whether the source is actually producing just as much light?

From what I understand they produce less light, although I don't have any precise figures to hand; the Farnell catalogue might help - they have pretty good product info.

[P. Funk]

Why can a white LED not be made?

 

LEDs only produce one frequency of light, and white is made up of several frequencies of light, so one LED cannot produce the "whole" white colour.

[niclights]

I have also been considering these cheap LED pars. I have allocated budget for Chromapanel CP300's, already having some 600's (which I love!) but now I'm wondering whether to use some of the P56's. Seems to be a mix of opinions at the moment. Can anyone else add more comments? Obviously you get what you pay for.

I am not interested in illuminating/repacing normal pars, just use for effect in an install. How is DMX dealt with? In/out + dip switch? Are colours reasonably consistent from unit to unit? How fast is dimming response under DMX control - ie. can you perform a reasonable strobe?

 

(Those pics would be awesome, though obviously it's difficult to capture how they really look.)

 

Cheers :)

[Guest lightnix]

There's an excellent Wiki page on LEDs to be found here, with a section on blue and white LEDs, among other things.

 

Very informative :)

[Light Console]

How is DMX dealt with? In/out + dip switch? Are colours reasonably consistent from unit to unit? How fast is dimming response under DMX control - ie. can you perform a reasonable strobe?

 

Right then, for my Eurolite P56's DMX is as you say, on 3 pin XLR, in out with DIP switch. Colours from unit to unit are very well matched. Dimming seems ok, they start flashing rather than dim towards the 0% end of a fade, this is not their strobe feature! That is dealt with on the 5th DMX channel and the strobe function seems to be very good, although it does make you feel sick as the colours chase through. Six units producing an out of sync slow strobe effect is quite amazing.

 

Compare

Blue @ 100%, vs 100w bedroom light, ps that cable has now been cut down to size!

[Germaine]

Hi guys,

I was looking at the showtec LED par as it seems to be able to do so much for such a small price, however I was put of by reading these threads and googling these items as I haven't found a product with an intensity channel. Minimac I think you mentioned that you'd found one in the showtec range but my research into this suggests the 4th channel is for chases etc and isn't intensity based? please tell me my research was wrong, I Hired some Arytons easycolour's recently (think that's what they're now called), and it took a fair bit more time to programme without the intensity channel,(fixtures were latter flashed to include this). I'd love to use these at an event I'm doing for a bit of dancefloor colour running of a frog or pearl and being able to fire an intensity chase of and then use the palletes for colour, this would make life so much easier than making lots of different chases.

I looked at the personality editor for the frog as well and didn't see anything there that would help, sorry if I've gone of topic but does anyone know of a can with intensity and doesn't this seem like a major oversite?.

 

Germaine

 

p.s. with so many more of these things coming out i.e. additive colour mixing, wouldn't it be great if desks started supporting this?

[Tomo]

Desks do support it, just not the lower-end or older ones.

 

The reason why LED pars don't have a fourth intensity channel is because it would take up four channels rather than the three required to describe all possible colours within the gamut.

 

However, there are some available that use the Hue Saturation Value/Intensity (HSV or HSI) colour model instead of RGB, which gives an intensity channel at the expense of needing much more processing power to implement, and giving different colour fade routes.

 

Hue - Base colour

(blue>purple>red>yellow>green>turquoise and back to blue, manufacturer's choice on where zero lies)

Saturation - Vibrancy of colour - 0 is white, 1 is bright colour

Value/Intensity - Brightness

 

There is a good wikipedia article here that explains the HSV colour model, and the transformation from RGB to HSV and vice versa.

 

Hue and Value are easy to visualise, but Saturation is harder to figure out - obviously if you have an HSV unit you can just play with it to see the effect.

 

You won't see this on cheap units due to the processing needed to convert an HSV control signal into the RGB levels that physically exist.

 

Chroma-Q make some LED stuff that uses HSI - Colour Block

[niclights]

Yup. The lack of intensity channel is a pain in the ****. Hopefully virtual dimmer function will be workable on the Pearl. I'm going to be buying some more Pulsar & possibly some of these cheap Showtec's very soon - a perfect opportunity for testing. (hint, hint! :( )

 

Tnx Robert for the info & pics. I've decided to go and order a couple to see if they suitable. My intention is to use lots of them as simple dancefloor downlight in conjuction with CP300's. Ex VAT from Thomann the 56's come in at just over £45. Will post with results!

[Leecey]

My boss at the hire company (SW London) I work at just got 4 of the Showtec LED Par56 on trial from thomann, cost about £45 each. I played around with them for a good hour and was pleasantly surprised. Yes, the output basically limits them to effects (architectural stuff worked nicely), they do blind you if you look right into them (but as discussed frosting would solve that) and dimming them slowly you do see a tiny bit of jumpiness.

 

On the plus size, I was satisfied with build quality (although I didn't try dropping them or anything), the range of colours was impressive, they look very nice doing chases, they were barely warm to touch and of course they require practically no power. Boss is keeping these four and ordering in another 20 next week.

 

Anyone wants anymore info on these particular units I'll do my best.

[Alec]

Anyone wants anymore info on these particular units I'll do my best.

 

Some photos of these in action side-by-side with conventional Par 56 lanterns would be great, maybe in a variety of colours. It would greatly help the "how bright" brigade to make a more informed decision.

[niclights]

Test units turned up this morning (ok, yesterday morning!) & so I was very impressed with Thomann speed.

 

I spent some time testing & did my best to take some photo's with el rubbisho cam and LD wobble hand.

Appologies for size of picture. I thought people would appreciate more detail rather than worry about screensize/bandwidth.

 

 

 

 

http://img68.imageshack.us/img68/5985/led38xa.jpg

 

 

(Light exit is approx 8' from floor, which is red)

 

1) Full white comparison with 650W PC Beam, N/C with beam zoomed to similar size.

2) Rear of unit

3) With/without quarter white diffusion. (these photo's taken with channels at minimum value to help the camera)

4) 100% R

5) 100% G

6) 100% B

7) Red diffusion comparison

8) Green diffusion comparison

9) Blue diffusion comparison

10) 100% RGB w/diffusion

11) 100% R&G w/diffusion

12) 100% B w/diffusion

13) Front of units

14) Cable entry

15) Full RGB direct.

 

 

Quality of the units were better than expected. Shell itself is strong - similar to any other parcan. It is not a standard can - the unit is solid, with the only opening being at the front. Yoke is a bit thin - similar to that on Vision pars.

The LED's themselves seem a little vulnerable. I think it is wise to make use of the gel frame for some protection.

There are ventilation slots for the transformer - a potential liquid entry point.

Rather stupidly, the yoke lines up directly with the XLR connectors when vertical and there is not quite enough space for a standard Neutrik XLR + cable!

 

Light output is good - as already mentioned, too bright to look at. Certainly adequate for effects, uplighting & highlighting.

Colour mixing is unsuprisingly basic. Primary colours are good, but some mixes are poor - especially yellow! Red seems to be the dominant colour and therefore causes problems with most mixes based on it. Halos of the colours used in a mix are noticeable, but some diffusion cleans this up. I found 1/4 white worked very well - removed the glare from direct view and helped smooth out the colours. This also doubles up as extra protection for the LED's.

 

DMX control is over 6 channels. 1,2 & 3 are RGB. 4 gives ready made colour mixes - a limited 1 ch version of using RGB. 5 gives strobe using colours/levels from RGB. This is of an equal on/equal off type - ie. the duration of the 'flash' increases as you decrease the speed. It does not have many speed options. IMO fast is too fast and the next step down is too slow (typical!) but thanks to the lamps quirky nature nothing here stays in time & so the slightly slower settings will work nicely when lamps are all randomly out of sync! Of course some might see this as a flaw. The final channel gives options to select built in effects, or sound to light etc.

 

Highest DMX Address is 127. This is rather limiting - maximum 21 individual units.

 

One problem I noticed was they seemed rather sensitive to something on the mains generated by my DF-50. Circuits would occasionally flicker. This occured randomly in both fixtures regardless of phase/circuit. Obviously the hazer must have been doing something naughty to my neutral or earth, but none of my other fixtures are affected. I have yet to test whist running a full rig. I wonder what they will make of Atomics? I will be investigating some mains filtering for the units.

 

 

Overall though I am impressed. I can't really fault this for the money and once I am satisfied I can solve the dirty mains issue I will purchase more. My only reservation is how long will the LED's maintain their brightness. From my understanding the key to high power LED's is heat dissipation. You can drive an LED as hard as like, but the amount of time it can last depends on how quickly you can remove the heat. Methinks these units aren't anything more than a circuit board with the LED's soldered to it. Only time will tell.

[Light Console]

I found the flickering on mine was caused by the switch at the back set to audio. When I set it to auto, the flickering stopped. I had DMX into the unit, but at all channels at 0 when I had the problem.