Pixel Par 660's

[Guest lightnix]

I wonder how much the ultra-bright LED's actually are?

"Normal" ultra-bright LEDs are about £1 each right now, The Pixelpar 660 uses 656 of them. 1 watt Luxeon LEDs are about £10 +VAT each at the moment with the Pixelpar90 using ninety of them (although Thomas probably get price breaks for buying them in huge quantities).

 

You probably wouldn't get much light out of them if you powered them with mains, though :wub:

 

...then again I supose LEDs arnt indestructable, although you'd expect them to be for that price!!

Nothing is completely indestructible, but LEDs come damn close and are far more robust than tungsten/discharge lamps ever will be. They also have far longer working lives, use far less power, produce much less heat and don't need gel. Apart from the occasional cleaning, LED units are "rig, focus and forget" units.

 

Yes, LED units are very expensive to buy, but the savings come in the long term and prices are falling. Here's a real life example...

 

There's a venue that I've been trying to convince to go the Chromabank route for a while now. At the moment they're using Coda groundrows, which cost around £20 in gel and £20 in labour to recolour, between ten and fifteen times a month, in each one of their three main conference rooms, making an approximate monthly cost of £1200-1800 in gel and labour alone. That's before you consider the replacement bulbs, the power they consume, the need for dimmers, the masses of heat they kick out and the negative impression they sometimes make on clients, who ask what "that burning smell" is.

 

I've convinced the chief lighting and technical chaps, but the short sighted accountants robots can't see further than the monthly figures and keep bleating that "LED lights cost too much", even though they will save so much in the long term and will have more than paid for themselves in five years or so.

[Just Some Bloke]

... the short sighted accountants robots can't see further than the monthly figures and keep bleating that "LED lights cost too much", even though they will save so much in the long term and will have more than paid for themselves in five years or so.

... and in five years' time LED battens will probably cost half as much as they do now! :unsure:

 

It's that age old conundrum - wait for the price to go down and guess when it's reached it's natural base, all the time missing out on great new kit, or buy now and 'waste' money on something that you could have got a lot cheaper just by waiting.

 

Personally I always go with hire until the sale price is affordable.

[Bill Jones]

CCT are soon to have a LED product to rival the pixel pars using the very latest ultra bright LEDS (brighter than the now standard 1watt luxeons) ABTT show should see it on show to everyone. Anyone wnating to know more please call me at CCT.

[Tomo]

"LED lights cost too much", even though they will save so much in the long term and will have more than paid for themselves in five years or so.

A lot of places work on a 2 or 3-year payback cycle.

If it won't pay for itself within 3 years, the accountants usually say "Forget it"

 

Shame really, as the lifetime of a generic theatre fixture or LED based non-moving fixture is closer to ten years. And the LED fixture probably won't want replacement lamps during that time.

 

Moving lights are a different kettle of fish obviously. Need a lot more maintainance and break more often, especially if you don't maintain them regularly enough.

[David Buffham]

They're not up to doing front washes or area lighting yet (although it won't be too long now).  They are best for backlight and specials at the moment and even then you should try not to make the throw more than about four or five metres.

 

I've been working on a show this week which uses a series of pixelline battens to colour wash the walls of a box-set in a studio theatre. So the flats are only about 10' high and the battens are rigged about 6" downstage of the flats, and no-more than a couple of feet above them. The coverage is really good, and in this situation brightness is not an issue except perhaps with the darker blue colours.

 

Give them 5 years and they'll be moving into theatres as front light.

 

Possibly, but there are a couple of issues other than brightness that would probably need to be addressed first

 

- slow blue fade up and downs are very steppy - the intensity steps up in really obvious discrete steps rather than fades. Its not so good for subtle transitions in theatre.

 

- there is a major colour shift as the unit's intensity changes. A slow fade up to an apricot kind of colour will pass through all kinds of reds and oranges. Even if the target colour has been marked into the blackout cue. Obviously the 'dimming' is simply done by RGB intensity so the colour shifts are bound to happen but they can look crap. (Its a bit like keeping the lamp on a VL5 permanently on and going from 'black' to your target colour just by adjusting CMY flags; you would go through all kinds of murk on the way)

 

I guess for both these issues the battens would need some other means of dimming their output to make them useful for subtle work, e.g. some kind of mechanical dimmer shutter

 

Possibly also a discrete true white output would be useful, as full RGB is still quite colourful!

[martinw]

- slow blue fade up and downs are very steppy - the intensity steps up in really obvious discrete steps rather than fades. Its not so good for subtle transitions in theatre.

This is because the reaction time of the LED to a change in its input current is so fast, that it is practically instant, hence you see each small step of the dimming curve as the level changes. With an incandescent lamp, the reaction time is very slow in comparison, and this has the effect of smoothing out the steps.

 

There are various fixes to this issue; firstly, ensure that you console's refresh rate is set as high as possible (if you can change it). When the console generates a cross-fade from one value to another, the more points between the start and end values that get sent to the fixture, the smoother the fade will appear. The maximum refresh rate of a console often varies, depending on how many parameters are changing at a specific time. The more work the console has to do (especially true for effects engine type stuff), the fewer refreshes per second it has time to do.

 

If you can, use 16 bit channels for LED fixtures, and make sure that any smoothing algorithms built into the fixture's software are switched on.

 

Check you have the latest software version for the pixellines, as Thomas may well have fixed this.

 

Martin

[benweblight]

How about a PAR64 shell with 3 mains cables? one for each colour.

now theres an idea...

If you mean 3 individual mains cables to 3 individual lamps.... then it's already been done! CPC sell a Rainbow par which looks like a bog standard Par 64 with 3x HPL575s in it, so you can RGB mixing with it.

 

Not sure what the end effect looks like, but have a search on the CPC site and you'll find it.

 

Terralec might do it too. Not sure.

 

Stu

I think he meant with blue leds

[Stu]

How about a PAR64 shell with 3 mains cables? one for each colour.

now theres an idea...

CPC sell a Rainbow par which looks like a bog standard Par 64 with 3x HPL575s in it, so you can RGB mixing with it.

I think he meant with blue leds

Well judging by the original post saying 3 mains cables I can only presume it was generally thought it might be using bog standard lamps, as you wouldn't need 3 mains cables for a lantern which had RGB LED mixing......

 

Stu

[MarcT]

...however the LEDs look promising for uses such as exhibitions and tv work... (cant seem to find a tv show right now that doesnt use the chroma banks... :) )

I think I spotted a load of Pixel Pars lighting whichever band Jonathan Ross had at the end of his show, a few weeks back...

 

Seem to be OK for TV!

 

Marc

[David Buffham]

- slow blue fade up and downs are very steppy - the intensity steps up in really obvious discrete steps rather than fades. Its not so good for subtle transitions in theatre.

This is because the reaction time of the LED to a change in its input current is so fast, that it is practically instant, hence you see each small step of the dimming curve as the level changes. With an incandescent lamp, the reaction time is very slow in comparison, and this has the effect of smoothing out the steps.

 

There are various fixes to this issue; firstly, ensure that you console's refresh rate is set as high as possible (if you can change it). When the console generates a cross-fade from one value to another, the more points between the start and end values that get sent to the fixture, the smoother the fade will appear. The maximum refresh rate of a console often varies, depending on how many parameters are changing at a specific time. The more work the console has to do (especially true for effects engine type stuff), the fewer refreshes per second it has time to do.

 

If you can, use 16 bit channels for LED fixtures, and make sure that any smoothing algorithms built into the fixture's software are switched on.

 

Check you have the latest software version for the pixellines, as Thomas may well have fixed this.

 

Martin

 

Hi Martin,

 

Thanks for the ideas. We don't have any control over the DMX refresh rate, but as the console is a Virtuoso DX I don't think that would be an issue (haven't had any problems in any other situations). The battens we were using were only 8 bit control over RGB, with no option for 16-bit.

 

I think a good solution in the future would be for the LED units to have DMX timing channels like moving lights have, then fades can be handled by the units themselves in the most optimum way.

 

As it is the slow fades are very distracting, and there was a similar issue with whatever units are installed in the alcoves in the pros in Les Mis in the West End which I saw a couple of weeks ago. I guess they are LED fixtures of some sort, but whatever they were they snap on to a low level and then step up. Which even on the extreme side of the stage is noticable in your peripheral vision.

 

I think LED fixtures are fantastic and are definitely a way forward for the industry. They just need refining to make them more acceptable for a theatre situation, but no doubt that will happen as the technology progresses!

 

Cheers,

David

[the kid]

I do think that LED's will become the way foward but they will not become big, in the terms of generic lighting big, for a while. The white LED's are way to expensive at the moment. I think that they will be like the moving fixtures, in some cases they are really useful and in other cases they are pointless.

[P. Funk]

FYI: the LEDs used in Les Mis are artistic license colourpipes