LED v Conventional Lighting Questions

[MaddieNevins]

Hello!

I'm writing a research paper for one of my tech theatre classes and was wondering if you guys could help me out. I'm writing about LED theatre lighting vs. conventional theatre lighting.

In your opinion:
- What benefits do LED's have for the theatre?
- What can conventional lighting fixtures do that LED's can't?
- Which type of fixture do you prefer?

Thanks for your help!

Maddie

 

[shiben]

Is this question part of your research (ie, would this be cited as an interview of some type)? Your last question is fairly simple to answer: it depends what your goal is with that particular instrument. Try looking up various articles in PLSN, LSA or other industry magazines and see what kind of LEDs people are using, and what they have to say about them. Thats probably your best place to figure out the answer to the first two questions.

 

[Les]

Hello!

I'm writing a research paper for one of my tech theatre classes and was wondering if you guys could help me out. I'm writing about LED theatre lighting vs. conventional theatre lighting.

In your opinion:
- What benefits do LED's have for the theatre?
- What can conventional lighting fixtures do that LED's can't?
- Which type of fixture do you prefer?

Thanks for your help!

Maddie

- What benefits do LED's have for the theatre?
LED's consume a fraction of the energy that conventional fixtures do, meaning more LED instruments can be put on a circuit. Also, many/most can be fully DMX controlled, which keeps your dimmers free for other uses.
LED's produce less heat, meaning they are safer to handle and your HVAC doesn't have to work as hard.
LED's don't need re-lamping (<50,000 hour diode life).
Most LED fixtures also have full color mixing capabilities which can replace several units which were once devoted to only one color per fixture.

- What can conventional lighting fixtures do that LED's can't?
Conventional fixtures are in general brighter and cheaper than most LED fixtures. Also, LED's have been known to have a poor dimming curve and throw awkward rainbow shadows. Some complain that the colors of LED fixtures are too unnatural. Also, since LED's are not a point source, it is more difficult to use them to project patterns.

- Which type of fixture do you prefer?
Right now -- Conventional. They're more affordable, more reliable, and currently more qualified for the typical theatrical lighting design.

 

[DELO72]

Some really basic pros and cons:

Conventional Theatre Lighting:
Pros:
-- High CRI (Tungsten Halogen lamps provide perfect color rendering of 100 CRI before they are gel'd), which means truer colors in fabric, paint, and skin tones on stage.
-- Brightest White capability
-- Beam Shaping (ERS fixtures)
-- Line Voltage (plug them into a dimmer and go!)
-- Low cost (comparitively) per fixture. Low maintenance costs.
-- Higher output capability than LEDs (currently...)
-- No need for fans (non-moving heads) or additional cooling so they are silent.

Cons:
-- Very hot (both to the touch and heat output)
-- Short life (lamp) compared to LEDs
-- The need for Gel to color the light.
-- You need multiple fixtures for multiple colors (unless you add a color changer/Scroller)
-- Very inefficient (Lumens per watt).

LEDs

Pros:
-- Longest life (10x -50x that of a tungsten Halogen lamp or Discharge source -- ALTHOUGH, that is deceptive as that is the life of the LED itself, and not the electronic drive component....) = lower maintenance.
-- Very bright, saturated color. Higher output than you can get with other sources as the filters in conventional lighting reduce the total light output the more saturated the color is.
--Very energy efficient. In most cases you are saving a lot of energy costs by using LED fixtures.
-- Very low heat. LEDs generate no heat from the front, and the only heat generated is at the back of the fixture.

Cons:
-- most require a driver or power supply (transformer- often external) as their power requirements are rarely line-voltage.
-- Fan or active cooling is often required to preserve the life of the LED and prevent the degradation of the phosphors and electronics. LEDs DO generate heat-- they just send it out the back, not radiate it from the front.
--Weight. Due to the need to manage the heat and thermal needs, LEDs have large heat sinks, which means they weigh a TON. The greater the output, the heavier the LED fixture (or more powerful the fans will be) will be do to the heat sinking and fans needed to cool it.
-- Very High Cost. Regular PARcan = ~$50. LED "PAR" = ~$2,000.
-- Difficult to match colors to that of Gels in conventional fixtures. You can get close in the hue, but the wavelength is not the same. For Concerts or Touring this is not a big deal. For a stage show in which the Costume Designer is sitting in the front row-- this is a VERY big deal...
-- Bining... ugh. Blue in one fixture does NOT = Blue in another. Or even fixture to fixture in the same model/company sometimes. Depends on the company, the cost, and their binning tolerances (or correcting software).


Currently LED fixtures work GREAT for Color Washes (Replacing R40 or MR16 Strip lights) for lighting a Cyclorama.

LEDs cannot yet replace Ellipsoidal fixtures or replace the beam quality/spread/CRI/White output of PARCans or Fresnels-- But stay tuned. A lot of great companies have products in the works that will completely disprove this last sentence in the coming months/years.

 

[Esoteric]

Actually Mark, Elation has a ELED Fresnel (replacement for a 500W fresnel) that is really, really nice. Add to that the CWWW PARs that are out there with some good diffusion and the tri-LED PARs, and you have replacements for most small fresnels and PARs.

Good ERS LED replacements are still 6 months or so away.

Also, all the LEDs I use take in line voltage, so that isn't an issue.

Cost is greater, but not as much as you are making it out to be. A really, really, really good, strong (over 40'-50' throws) LED PAR will run you $1300. You can get tons of good stuff in the $500 range.

Mike

 

[JD]

One big problem with current RGB and RGBY LED fixtures is that LEDs are by nature monochromatic. The result is that if you look at them through a spectrum diffuser you will see a handful of very bright spikes with little in between. In the real world, you can not predictably gel them in white mode, and there are some unnatural hits and misses when you try to color mix. A conventional fixture tends to give you a very broad and even spectrum much like the sun. LEDs, by their very nature do not possess a "color temperature."

To answer these problems we see the "white" LED. Actually, there is no such thing. A white LED is actually a UV LED with some phosphorous to convert it's output to visible light. As such, the spectrum will be the same as a CFL using the same phosphate.

We have a ways to go with LEDs, but the end result will be very efficient fixtures! I would have no problem using them in "Rock" applications, and other applications where fine color control and flesh tones are not high on the priority list. For now, conventional do a better job with fine lighting. There is however no reason they have to be exclusive either way. You may want to use conventional FOH, but LED for stage objects, or background.

Things are only going to get better as time moves on. Unless, as reported in this month's LD magazine, there is a lack of interest in developing LED fixtures due to the profit margin manufacturers make on dimmer systems !

 

[xander]

Things are only going to get better as time moves on. Unless, as reported in this month's LD magazine, there is a lack of interest in developing LED fixtures due to the profit margin manufacturers make on dimmer systems !

I was just reading that article (Article link) yesterday and I found myself a little bit baffled. Believe me, I always assume that for-profit companies will do anything for the bottom line, but I thought this author was just completely ignorant (for lack of a better word). The majority of fixture manufacturers are just that, fixture manufacturers. They don't even make dimmers, so why would they care if their fixtures don't use dimmers? Yes, there are a few manufacturers that do both, Strand and Electronic Theater Controls being the big two, and they are indeed at the back of the line as far as LED innovation is concerned (one might also note that these two companies don't have much in the way of discharge fixtures either). They are the exception though, not the rule. The vast majority of fixture manufacturing companies out there are indeed putting millions of dollars into R&D of LEDs and we are starting to see the payout with the introduction of LED profile fixtures. There is still a ways to go before "conventional" fixtures are obsolete. The introduction of the discharge lamp (mainly in moving lights) did not mean the ruin of the SCR dimmer, so why would LEDs?

/end completely off topic rant

-Tim

 

[BDS0111]

Yes, there are a few manufacturers that do both, Strand and Electronic Theater Controls being the big two, and they are indeed at the back of the line as far as LED innovation is concerned

I would have to disagree. I think ETC is at the forefront of LED innovation. Looking strictly at the conventional segment... In my eyes, the Selador line, especially he Vivid and Fire, are the only LED fixtures on the market that can even come close right now to actually replacing a conventional instrument such as the Source Four Par.

 

[xander]

I would have to disagree. I think ETC is at the forefront of LED innovation. Looking strictly at the conventional segment... In my eyes, the Selador line, especially he Vivid and Fire, are the only LED fixtures on the market that can even come close right now to actually replacing a conventional instrument such as the Source Four Par.

I do agree with you that the "the Selador line....are the only LED fixtures on the market that can even come close right now to actually replacing a conventional instrument," but I don't think that disproves my point. First of all, my point was that ETC is one of very few companies that make fixtures and dimmers, not that their LED fixtures are not good. Secondly, take a look at when the Seladors came out. That was several years after LEDs started hitting the market; not exactly cutting edge in that regard. Thirdly, ETC didn't even design the fixtures, they just bought Selador to get in on the market.

 

[derekleffew]

... but I thought this author was just completely ignorant (for lack of a better word). ...

I concur. I felt the writer's premise was flawed, and even somewhat offensive to dimmer manufacturers. My opinion of Live Design lessened even more with the publication of this substandard article.

 

[Esoteric]

I have to disagree on Seladors being the only units on the market that can replace a unit like the Source 4 PAR. If you are using a lot of saturate colors there are tons of LED fixtures out there that would do a better job than a Source 4 PAR. The Selador units are great, but not because of their output necessarily, but because of their accessories and their overall quality (as well as customer service quality).

The article is not the greatest, but honestly ETC is not on the cutting edge of LED development. I can not speak to why, but they are fulfilling the needs of their market segment like any good company. It is just that 90% of theaters/touring groups/touring houses/etc are not in their market segment (when it comes to LEDs, they cover a much wider market segment in Dimmers and Control).

Mike

 

[NevilleLighting]

There are a few questions I am interested in with the LED vs. conventional discussion.
1. Does anyone worry about LED lifespan?
2. Do you have concerns/issues at all with LED lumens output vs. conventional?
3. There is a wide range of LED prices and with the higher prices comes more capability. Is the higher price point worth the dollars? Or, does the higher price put the units out of your fiscal range?
4. Concerns about dimming range?

 

[Kelite]

I concur. I felt the writer's premise was flawed, and even somewhat offensive to dimmer manufacturers. My opinion of Live Design lessened even more with the publication of this substandard article.

That makes two of us, Derek. The seemingly pointed jab at an obviously unnamed manufacturer made me feel less likely to agree to a phone interview with him about anything market related.

 

[DELO72]

To answer these problems we see the "white" LED. Actually, there is no such thing. A white LED is actually a UV LED with some phosphorous to convert it's output to visible light. As such, the spectrum will be the same as a CFL using the same phosphate.

Actually, UV LEDs (below 380nm) are extremely difficult to manufacture. A white LED is actually a Blue LED with a yellow phosphor coating. The actual pigments in the phosphor control the spectrum, just like in a fluorescent lamp.