FORUMS: list search recent posts

LED Lights Squealing... like a horde of pigs trampling my soul.

COW Forums : Lighting Design

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
Travis Roesler
LED Lights Squealing... like a horde of pigs trampling my soul.
on Jan 16, 2014 at 8:36:09 pm

The title pretty much says it. I'm actually picking up some of the squealing noise that I get from my LED lights.

They are virtually silent at full strength, but any adjustment yields a slight screeching sound... one that I didn't really think would be an issue. It is now a slight issue.

I have a set of the genaray LED's. Does anyone know for sure if there is a different brand that I can buy which will 100% NOT squeal... or make any sound whatsoever?

Right now, my reason for choosing LED' was to keep the temperature in my office down, and also my ability to mount them to the ceiling for absolute convenience (and with my manfrotto arm thingies, some great adjustability :-)

I'm open to suggestions, but right now, I'm not sure these lights are working out for me.

Thanks for your help guys

---Trav


Return to posts index

Rick Wise
Re: LED Lights Squealing... like a horde of pigs trampling my soul.
on Jan 16, 2014 at 9:04:20 pm

Leave the lights up at 100%. You can control the intensity of these lights with ND gels, which come in various strengths. You can buy them either by the sheet or the roll. Probably start with a few ND3 gels, which cuts the light by one stop. See how that works.

You can also cut down on the intensity by adding diffusion to the front of the lights. That will make the light softer, and also cut intensity. How much the diffusion cuts intensity depends on which you use. There is a large selection from which to choose. Lee has a terrific table of diffusions with f/stop light-loss details here: http://www.leefilters.com/lighting/diffusion-list.html. Be sure to scroll down. The list is long and complete. One of my staples is light grid cloth, elsewhere referred to as 1/2 grid cloth. But DPs have many favorites.

Yes, it's irritating that the vaunted dimmabilities of these lights turn out to be less than practical. But they are relatively cheap.... And with a bit more effort you can control their output.

Rick Wise
Cinematographer
San Francisco Bay Area
http://www.RickWiseDP.com


Return to posts index

Mark Suszko
Re: LED Lights Squealing... like a horde of pigs trampling my soul.
on Jan 16, 2014 at 10:11:43 pm

The squeal is from the high-frequency switching on and off that is used to "dim" an LED. Flo lights have had noisy ballast problems, a somewhat similar problem. The flo issue is solved with an more expensive, higher-tech ballast, or isolating the ballast remotely in a quiet box. The LED noise problem is "solved" with better control electronics... or by Rick's more practical method.

Some LED banks get their brightness control by turning off a third or a half of the LED's in the array with a selector switch. That kind of system would likely be completely silent, as well as power-efficient.


Return to posts index


Travis Roesler
Re: LED Lights Squealing... like a horde of pigs trampling my soul.
on Jan 18, 2014 at 1:21:51 am

Rick,

Insanely helpful… thank you.

I played around all day cutting some diffusion cloth and paper that my editor had hanging around his place. The light in the room is now more pleasant, the sound is completely gone, and I even need two fewer lights to light my background. It's pretty sweet.

I'm going to hang up my gloves on the project and send you guys a clip from the next video I put out!

---Trav


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]