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[Earl Teigrob]

I've been looking at getting some LED par lights and have wondered how the rating work. For example, When rated at 18 LEDs at 18w each and is 'six in one', what does this mean?
My guess is that in each LED is a cluster of (in this case 3w) leds in different colors.
For example

Red 3w
Blue 3w
Green 3w
White 3w
Amber 3W
UV 3W

So the total for one LED is 6 x 3 = 18w. Is this correct?

So if the light is 100%  on one color, the total light output is 18 x 3w = 54w

That is a far cry from the 324w the light would appear to have.

Or am I missing something?

Thank you.

[Jeff Lelko]

Yes, in general that's correct.  As a disclaimer, not all multicolored LED light sources weigh evenly between colors, but yes, that's essentially a fair statement.  LED lights are an additive light source, meaning that you only add the discrete colors in amounts that you need to create the color and output you intend.  That generally means you rarely use full output of a fixture.  In contract, subtractive light sources (gelling a par or CMY mixing) work by masking various wavelengths of lights that come from a full-spectrum source.  Subtractive works best for light colors, additive excels in deep, dark colors.  Hope this helps! 

[Mark Cadwallader]

You are basically correct. However, watts don't tell you anything meaningful. The information you should look at is the photometric specification. That tells you how much illumination of a surface there is, as measured at one or more distances. That and the beam and field measurement (in degrees of spread) will give you useful data. Lumens don't measure illumination of a surface; lux is the correct unit to consider.

If there is no photometric data available for a lighting fixture, that's an indication that the fixture isn't intended for serious lighting use. (But they might have pretty effects, anyway.)

[Paul G. OBrien]

Earl your math is correct. As indicated the relative brightness a fixture produces depends upon the beam angle and for uplighting purposes a narrow beam is typically used... something like 15-20deg. For this use 50w of LED output would be quite good, below is a pic of my uplight fixtures that are only 27w per color(9 18w hex diodes). One thing I would suggest for your purchase is to buy fixtures with wireless DMX built in, battery powered is also an option but in my experience is if little use as the battery charge doesn't last from setup time all the way to the end of an event which is often 12-14hrs for me.

https://c1.staticflickr.com/5/4874/46047072464_df8da155e3_b.jpg

[Earl Teigrob]

Thank you for all your responses. This is good information to know. My use if for a dance I put on once a month and is very Non-Critical.
In fact if the lights do work I will make no difference.

With that in mind, I am looking to get some of these lights.

https://www.aliexpress.com/item/Aluminum-shell-2pcs-lot-18x12W-RGBW-Led-Par-Light-DMX-Stage-Lights-Business-Lights-Professional-Flat/32800418414.html?spm=a2g0s.13010208.99999999.267.30453c00SSXmGT

They are bright, aluminum case, fanless (silent) and relatively inexpensive. The company that sells them has a very good rating and reputation with there other lights. Any Thoughts?

[Jeff Lelko]

Any Thoughts?

Glad to hear our input is useful.  As far as the ebay and direct from China lights go...  It's a gamble.  Several members here such as Steve Garris have had excellent luck with the very cheap generic fixtures.  If that's the route you'd like to go I'd suggest searching the forum for his suggestions.  I personally choose to use at least lower-end name brand fixtures such as Chauvet SlimPar Pros and above - it just aligns better with my business model. 

Either way, I'd never spend $123-180 per fixture on LED Pars from AliExpress.  $30?  Maybe, if it fit what I needed.  For the same $123-180 you're in SlimPar territory, and I'd take one of those anyday over a generic fixture.  Output quality aside, I know I have a warranty that will be honored and replacement parts that will be available - two things that are very scarce with direct from China fixtures.  I vote to either get the $30-60 lights that Steve often recommends or spend the budget you have now on something from a reputable supplier.  Hope this helps!

[Jason Fultz]

Thank you for all your responses. This is good information to know. My use if for a dance I put on once a month and is very Non-Critical.
In fact if the lights do work I will make no difference.

With that in mind, I am looking to get some of these lights.

https://www.aliexpress.com/item/Aluminum-shell-2pcs-lot-18x12W-RGBW-Led-Par-Light-DMX-Stage-Lights-Business-Lights-Professional-Flat/32800418414.html?spm=a2g0s.13010208.99999999.267.30453c00SSXmGT

They are bright, aluminum case, fanless (silent) and relatively inexpensive. The company that sells them has a very good rating and reputation with there other lights. Any Thoughts?

I have  Experience with those  particular lights.
They are light in weight,  small ,but not very bright in actual use.
I would suggest that you find some of the 7x10 watt lights.
Cost wise a little more but way more useable output.
I have a pretty good handful of both . The smaller ones like in your link will provide some was up a wall, but its oversll pretty dim and if you have as anything else going on they will soon be washed put by brighter stuff.

[Earl Teigrob]

Ive got some 7 x 12w (3w per led color) but wanted brighter lights.

These are 18x15w (3w per led color) so they should be much brighter. I realize that lumin output is not always exactly the same but normally fairly close for a give wattage. This is 18x3w per color vs 7x2.5w per color in a 7x10. This is going to be way brighter.

I have  Experience with those  particular lights.
They are light in weight,  small ,but not very bright in actual use.
I would suggest that you find some of the 7x10 watt lights.
Cost wise a little more but way more useable output.
I have a pretty good handful of both . The smaller ones like in your link will provide some was up a wall, but its oversll pretty dim and if you have as anything else going on they will soon be washed put by brighter stuff.

[TJ (Tom) Cornish]

As has been pointed out by others, comparing brightness based on spec sheets is difficult.  The number and wattage of emitters is important, but so is beam angle.  The best judge of absolute brightness (not considering beam angle) in my experience is the electrical draw of the fixture - e.g. a fixture that draws 50 watts will be half as bright as a fixture that draws 100 watts all else equal. 

Beam angle makes a huge difference in apparent brightness - don't underestimate this.  A narrow beam fixture will seem much brighter than a wider angle fixture of the same wattage, but it may not cover what you need it to cover.

[Earl Teigrob]

Tom, Thank you. I totally agree with your statement. More wattage equates to more output in general, given a bit of variation between manufactures. I totally get that a narrower beam angle looks brighter. I can't see anything wrong with these lights so im going to give them a try. cross my fingers. xx

As has been pointed out by others, comparing brightness based on spec sheets is difficult.  The number and wattage of emitters is important, but so is beam angle.  The best judge of absolute brightness (not considering beam angle) in my experience is the electrical draw of the fixture - e.g. a fixture that draws 50 watts will be half as bright as a fixture that draws 100 watts all else equal. 

Beam angle makes a huge difference in apparent brightness - don't underestimate this.  A narrow beam fixture will seem much brighter than a wider angle fixture of the same wattage, but it may not cover what you need it to cover.

[ProSoundWeb Community]