How bright can LEDs be?

Kevin Maxwell

Kevin Maxwell

Junior
Feb 6, 2011
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How bright can LEDs be?

A lot of people complain that it is hard to see the indicators on a digital mixer when used outdoors. Well I have had the exact same problem and sometimes even worse seeing them on an analog mixer outdoors. But usually on an analog mixer there is a physical button that you can (not always easily) tell if it is up or down. With digital you are really relying on being able to see the indicators.

Are LEDs just not capable of being bright enough? Every digital mixer that I have used to the best of my knowledge has the ability to change the intensity of the indicators and it is usually a separate control from any other. You don’t want it to be too bright when used indoors but they never seem to be bright enough outdoors. There is or was one analog console that used blue lights as indicators that indoors they were just too bright and there wasn’t any way to turn them down. That wasn’t good and it was the only thing I didn’t like about the mixer.

So why are the LED indicators not bright enough? Is it too expensive to use brighter LEDs or are they not made as bright as they would need to be? Or do the manufactures not realize these products are used in sunlight situations where it is critical that we be able to see the LEDs and we can’t?

I don’t want any discussion about tents, I always use one because I don’t want to get sun burned and I want to be prepared in case of a popup shower. But even with a tent it is difficult to see the LED indicators. That is until the sun goes down and then I many times need to turn down the intensity of the panel lights. I have even turned down the monitor indoors when the house lights all go out. On one console I used the external monitor had no overall intensity control there was just separate R/G/B controls so I turned them down one at a time.
 
Re: How bright can LEDs be?

Hi Kevin,

I have a three-watt LED flashlight that will fry eyeballs in daylight!

My guess is it would not be a big deal to have brighter LEDs in mixers. The penalties being a slightly larger power supply and a bit more heat.

Am interested to hear what manufacturers have to say...

Thanks and good health, Weogo
 
Re: How bright can LEDs be?

Modern leds are typically an order of magnitude brighter than the sun, so it is the filtering, focusing and diffusion that decides how "dim" they are and how vulnerable they are to ambient light. Placement is important too, leds recessed behind the cover plate are much more consistent than traditional style leds that protrude through.
In most applications, the leds are not as bright as they can be, they are often limited by resistors that could be replaced to allow a lot more current, but then the power supply and the control circuitry would have to be able to keep up.
 
Re: How bright can LEDs be?

Just joined the forum so please excuse any mistakes.
I was trying to figure this out myself as to why manufacturers dont put brighter leds on consoles.
I don't think it's a power issue though. I do location sound too at times and for that my preferred mixer/recorder are Sound Devices and on these, the meter leds can be made dazzlingly bright even in the sun if need be. The recorders ofcourse are portable amd run on batteries and while the brightness does affect the battery life a little, it not a huge impact.
With mains power, im sure you could go a whole lot more!
 
Re: How bright can LEDs be?

LED's generate heat, but don't like being hot. So if you're outdoors in the sun there's a double heat problem (sunlight on the surface and the LEDs themselves). So thermal management is an issue. The other issue is just that everything ahead of the LEDs have to be beefed up - power supply, control circuitry, interconnects between circuit cards, etc. At some point you've lost the price battle over something that won't matter in the least under showroom lighting.
 
Re: How bright can LEDs be?

I would say the biggest factor is being able to dim every LED on the board so that it doesn't become part of the light show in darker applications.
picture that most of the LEDs on the board are turned on and off by meter circuits or other things, and making them all dimmable wouldn't be fun.
So designers picked a happy (unhappy) medium and stuck with it.

Jason
 
Re: How bright can LEDs be?

Jason Lavoie said:
I would say the biggest factor is being able to dim every LED on the board so that it doesn't become part of the light show in darker applications.
picture that most of the LEDs on the board are turned on and off by meter circuits or other things, and making them all dimmable wouldn't be fun.
So designers picked a happy (unhappy) medium and stuck with it.

Jason
Click to expand...

Bingo. The issue with dimming LEDs is that their dimming range isn't all that great. You can adjust the brightness somewhat by adjusting the voltage, but unlike a traditional lamp, the difference between enough voltage for on and full brightness isn't very linear. To get dimming beyond that you have to do things like pulse width modulation that turns the light on and off for durations of time so it appears dimmer. With potentially hundreds of LEDs on the board, this will increase costs pretty quickly.

Since MOST boards aren't going to be used full time in direct sunlight, the decision to match brightness for indoor use or dark room use was a better match.
 
Re: How bright can LEDs be?

From what is being said about the problems with dimming an LED that would be bright enough I wonder if it would be cheaper to design it with dual LEDs a dim one for indoors and a bright one for outdoors. Or to design a dual LED one that has both bright and dim functionality in it. This would probably not be something that could be easily retrofitted into existing mixers but might be able to be done in a new design.

I am not the kind of person that likes to accept the status quo I like to come up with solutions to problems. And seeing the indicators on a digital mixer out of doors is a problem that I have not seen anyone address completely yet.

But I must also say I appreciate everyone’s input but I would really like to hear from someone with experience manufacturing these kind of things. But we will probably not get that. Because of having to use our real names (which in general I thing is good) it makes it hard for someone to talk about many things. I myself am restricted in a lot of what I can say in public because of NDAs and things like that.

I was looking into LEDs for something else a few years ago and maybe I need to look again at some of those sources. I think there may have even been a LED forum I had visited.
 
Re: How bright can LEDs be?

Brian jojade said:
Bingo. The issue with dimming LEDs is that their dimming range isn't all that great. You can adjust the brightness somewhat by adjusting the voltage, but unlike a traditional lamp, the difference between enough voltage for on and full brightness isn't very linear. To get dimming beyond that you have to do things like pulse width modulation that turns the light on and off for durations of time so it appears dimmer. With potentially hundreds of LEDs on the board, this will increase costs pretty quickly.

Since MOST boards aren't going to be used full time in direct sunlight, the decision to match brightness for indoor use or dark room use was a better match.
Click to expand...

LEDs can have their intensity varied over several orders of magnitude given appropriate driver circuitry. In fact, the dimming performance of LEDs exceeds that of incandescent filaments because there's no pesky filament preheat to deal with at turn-on. You just need to remember that the intensity of an LED is primarily a function of current, not voltage (an incandescent lamp is similar), and that the IV curve is rather steep.
 
Re: How bright can LEDs be?

From what I can tell, the issues are primarily cost and driver circuitry (more cost). A mid-power LED may be 3x or more the cost of a cheapo indicator LED, and typically requires more current than can be sourced from a microcontroller pin. So to drive the LED to its full potential requires at least an additional transistor per indicator (note that this also applies to strings of LEDs used in place of a single LED). This also means more space on the (likely already cramped) PCB. Additional power consumption also comes into play, especially on larger devices.

There are other solutions beyond simply increasing the intensity of the indicator LEDs, but those also have their own tradeoffs. Realistically, it's probably best if the console designers actually try their consoles outdoors, and take notes...
 
Re: How bright can LEDs be?

Hi Kevin,
The way I see it, the biggest problem is that with a digital board, you are always looking at lights.
With an analog board, the controls were not continuous. EG, you could see where the knobs were positioned.
On a digital board, the knobs only turn, they do not show you where they are. You need to go to a screen to see where the knobs are positioned.
So, yes, the lights were a problem on an analog board, but there were a lot less of them.
Once you got passed the assigns, and mutes, that was it. Plus, those were just lights, not a readout. So seeing the lights was a lot easier than reading the LEDs.
 
Re: How bright can LEDs be?

Rob Timmerman said:
From what I can tell, the issues are primarily cost and driver circuitry (more cost). A mid-power LED may be 3x or more the cost of a cheapo indicator LED, and typically requires more current than can be sourced from a microcontroller pin. So to drive the LED to its full potential requires at least an additional transistor per indicator ...
Click to expand...

Exactly, I would imagine that it is mainly the cost and design complication (more cost) of adding led drivers and control circuitry that limits what can realistically be done in any budget console.
Driving a huge amount of leds would of course be easy if one could use one of the chips that are available for 48- 64 or even 96 led control, but as long as sane persons don't want to fill up their consoles with pwm noise, I guess there are no easy solution to having a huge range that covers everything.
Actually, giving yourself the ability to do whatever you want with leds inside the control surface is probably a good argument for keeping the control surface and the audio processing separate.
Seems to be a few sound reasons why sonically and technically, buying a tent is the best solution :D~:-D~:grin:
 
Re: How bright can LEDs be?

Per Søvik said:
Exactly, I would imagine that it is mainly the cost and design complication (more cost) of adding led drivers and control circuitry that limits what can realistically be done in any budget console.
Driving a huge amount of leds would of course be easy if one could use one of the chips that are available for 48- 64 or even 96 led control, but as long as sane persons don't want to fill up their consoles with pwm noise, I guess there are no easy solution to having a huge range that covers everything.
Actually, giving yourself the ability to do whatever you want with leds inside the control surface is probably a good argument for keeping the control surface and the audio processing separate.
Seems to be a few sound reasons why sonically and technically, buying a tent is the best solution :D~:-D~:grin:
Click to expand...

We have tents and we always use them. It didn’t make it easy to see the indicators. They could be seen but it wasn’t easy.
 
Re: How bright can LEDs be?

Kevin Maxwell said:
We have tents and we always use them. It didn’t make it easy to see the indicators. They could be seen but it wasn’t easy.
Click to expand...

Black roof tent? Only thing that really works, except dark blue that is only slightly worse.
I used my white roof tent once (the one I use for motorsport because it gives better working light than daylight :)~:)~:smile: ), back when I used an analog mix and outboard, that was not very good at all. I can imagine how horrible it would have been to use it on a bright day with the X32.
 
Re: How bright can LEDs be?

Per Søvik said:
Black roof tent? Only thing that really works, except dark blue that is only slightly worse.
I used my white roof tent once (the one I use for motorsport because it gives better working light than daylight :)~:)~:smile: ), back when I used an analog mix and outboard, that was not very good at all. I can imagine how horrible it would have been to use it on a bright day with the X32.
Click to expand...

Yes the tents are white roofed. I think I mentioned it somewhere else when the subject of tents came up. I was wondering if any one made a tent with a white outer surface and a dark non-reflective inner surface. I even use a sidewall to block the sun when it comes in from the side. I feel that a black roofed tent would turn the inside of it into an oven.

At least the location where I do most of the outdoor shows we are set up with the sun setting to our (house) left. At the beginning of this season we started to use a new tent (exact same model just not worn) and it took me one show to realize that one of the guys put the roof on too tight, it was as tight as a drum head and it was affecting the sound in the tent. I loosened it up and no more problems.

Is there any digital mixer out there that the indicators look as good in sunlight as they do indoors.

BTW I asked this (LED brightness) question on a forum where LEDs are discussed. Here is a link to that discussion.

http://www.candlepowerforums.com/vb...-LEDs-in-electronics-be&p=4530356#post4530356
 
Re: How bright can LEDs be?

Of course it can be done, but the expensive consoles will sell with or without that feature, and the budget consoles can't even consider it.
a quick tally of the X32 brings me to 692 LEDs, not including the actual main screen backlight. to do what you're asking means upgrading every one of those, adding potentially hundreds of transistors if they need to be PWM'd, potentially upgrading the power supply, potentially upgrading or changing the cooling.
It's one of those design decisions where I wouldn't be surprised if they already had the discussion of 'how dim can we make the LEDs before too many people complain'

Jason
 
Re: How bright can LEDs be?

Tim Padrick said:
Someone needs to try spraying the inside of his tent with black PlastiDip.
Click to expand...

Good idea :thumbup: , might become messy though. One possibility is to use two tops, a white on top of a black one. Some tents are too tight for this to work, but some are fine.
 
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