How bright can LEDs in electronics be?

TheMAXX · Oct 22, 2014

How bright can LEDs in electronics be?

The application is in a digital audio mixer that is used outdoors and indoors.

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 and those panel lights usually aren't LEDs. 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 or are they too expensive to use in this type of gear? 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 if they were capable of being bright enough what are the other problems introduced? Can the same LED be bright and without a problem also be very dim?

Or do the manufactures mixers 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?

Would it 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.

I would really like to hear from someone with experience manufacturing this kind of thing.

Norm · Oct 22, 2014

Not an answer but a question.

Do you have shade over the mixing desk?

Norm

RoGuE_StreaK · Oct 22, 2014

TheMAXX said:
Can the same LED be bright and without a problem also be very dim?

Yes.

TheMAXX said:
Or do the manufactures mixers 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?

Yes.

Simplistically speaking it's a matter of how much current is applied, and whether the LED in question can handle that amount of current. Most LEDs will produce light to current levels waaaaaay down, producing barely a glimmer. Going up, depends entirely on the LED, which probably depends on cost and availability; ye olde bar-graph LEDs have been around since like the 80s, so you could well be dealing with 30 year old technology. Are vastly brighter bar-graphs available? Don't know. Could they be made? Definitely. But it may be that no-one has asked for them. (just using the bar-graph as an example).

I don't know how much brightness is required for direct sunlight. But consider DRLs (daytime running lights) on cars, these are made specifically to be well-and-truly visible in broad daylight. So yeah, the technology definitely exists, just sounds like the manufacturers haven't considered it, or haven't considered it being worthwhile.

TheMAXX · Oct 22, 2014

Norm said:
Not an answer but a question.

Do you have shade over the mixing desk?

Norm

Yes I use a tent because I don't want to get cooked in the sunlight or have the equipment rained on in the event of a pop up shower, but it is still a problem seeing the indicators. And I am not even talking about the screens. That is another whole different subject. Some people don't use a tent I don't know how they see anything at all on these mixers.

DIWdiver · Oct 23, 2014

RoGuE_StreaK said:
Yes.

Yes.

Simplistically speaking it's a matter of how much current is applied, and whether the LED in question can handle that amount of current. Most LEDs will produce light to current levels waaaaaay down, producing barely a glimmer. Going up, depends entirely on the LED, which probably depends on cost and availability; ye olde bar-graph LEDs have been around since like the 80s, so you could well be dealing with 30 year old technology. Are vastly brighter bar-graphs available? Don't know. Could they be made? Definitely. But it may be that no-one has asked for them. (just using the bar-graph as an example).

I don't know how much brightness is required for direct sunlight. But consider DRLs (daytime running lights) on cars, these are made specifically to be well-and-truly visible in broad daylight. So yeah, the technology definitely exists, just sounds like the manufacturers haven't considered it, or haven't considered it being worthwhile.

a big +1!

If you want a perfect example of small LEDs that are very visible in sunlight, just drive around a little. How many cars do you see with center high mount stop lamps (CHMSL, or third brake lights) that look like a row of small dots? Every one of those dots is a CHMSL led. They've been around for 20 years or more.

As an engineer and designer of LED drivers, I can tell you it's easy to make an LED less bright. At some point they will suddenly stop making light, but that's usually at a point where you are already having a VERY hard time seeing if they are on or not. There is one manufacturer who recommends not running currents below 11-12% of maximum, but even those can be dimmed to 1% or less using PWM. From a club atmosphere to bright sunlight, you'd probably want about 100:1 change in brightness, maybe more if you want to be inconspicuous in the club.

Bright LEDs are more expensive, and they take more power to run, but that's a poor excuse if you are shelling out $1000 or more for a piece of equipment. I'd bet everyone in your supply chain falls into one of three categories:
1. Hasn't realized these are used outdoors, and that it's a problem.
2. Knows it's a problem, thinks it isn't worthwhile addressing it.
3. Wishes someone would do something about it, but doesn't know how to make it happen.

What you can do is make some noise. At least some manufacturers listen to sales reps and customers. The more people you can get to complain in ways that will get back to the manufacturers, the more chance you have of getting one to address your needs. And if you can get one manufacturer to make a big marketing deal of "daylight readable", it will rapidly become a must-have, and you will never have that problem again. Well, at least if you pay attention to the equipment you buy.

In the meantime, don't feel like you are alone. I just bought a new (2015) Subaru Forester. The round, relatively featureless climate control knobs have only one indication of where they are pointed: an LED mounted in the rim of the knob. This is awesome at night when the only things you can see on the dashboard are those that are deliberately lit up. But in the daytime, it's so dim that it's hard to see and you have to really look at the knob. A quick glance just won't cut it. All they'd have to do is paint an arrow on the knob. Or mold in an indicator. In this day of digital controls, auto dimming headlights and auto darkening rear-view mirrors, there's no excuse for screwing up something like this that worked perfectly well 20 years ago, but they did. And they're selling millions of them.

TheMAXX · Oct 23, 2014

DIWdiver said:
a big +1!

If you want a perfect example of small LEDs that are very visible in sunlight, just drive around a little. How many cars do you see with center high mount stop lamps (CHMSL, or third brake lights) that look like a row of small dots? Every one of those dots is a CHMSL led. They've been around for 20 years or more.

As an engineer and designer of LED drivers, I can tell you it's easy to make an LED less bright. At some point they will suddenly stop making light, but that's usually at a point where you are already having a VERY hard time seeing if they are on or not. There is one manufacturer who recommends not running currents below 11-12% of maximum, but even those can be dimmed to 1% or less using PWM. From a club atmosphere to bright sunlight, you'd probably want about 100:1 change in brightness, maybe more if you want to be inconspicuous in the club.

Bright LEDs are more expensive, and they take more power to run, but that's a poor excuse if you are shelling out $1000 or more for a piece of equipment. I'd bet everyone in your supply chain falls into one of three categories:
1. Hasn't realized these are used outdoors, and that it's a problem.
2. Knows it's a problem, thinks it isn't worthwhile addressing it.
3. Wishes someone would do something about it, but doesn't know how to make it happen.

What you can do is make some noise. At least some manufacturers listen to sales reps and customers. The more people you can get to complain in ways that will get back to the manufacturers, the more chance you have of getting one to address your needs. And if you can get one manufacturer to make a big marketing deal of "daylight readable", it will rapidly become a must-have, and you will never have that problem again. Well, at least if you pay attention to the equipment you buy.

In the meantime, don't feel like you are alone. I just bought a new (2015) Subaru Forester. The round, relatively featureless climate control knobs have only one indication of where they are pointed: an LED mounted in the rim of the knob. This is awesome at night when the only things you can see on the dashboard are those that are deliberately lit up. But in the daytime, it's so dim that it's hard to see and you have to really look at the knob. A quick glance just won't cut it. All they'd have to do is paint an arrow on the knob. Or mold in an indicator. In this day of digital controls, auto dimming headlights and auto darkening rear-view mirrors, there's no excuse for screwing up something like this that worked perfectly well 20 years ago, but they did. And they're selling millions of them.

Thank you. And from someone else in CT too.

Can I quote your reply and paste it in a couple of sound forums where I posted a very similar question? Or would you prefer I post a link to this forum?

DIWdiver · Oct 23, 2014

It's a public forum. I believe you should be allowed to do whatever you want with my reply. It would be quite rude to claim it as your own work, but if you are advancing the public good, even that might be forgiven. If you give credit where it's due, I'm happy with anything you choose to do. Your loyalty to the forum and those in it should be your guide. If we haven't yet earned your loyalty, then respect will suffice.

SemiMan · Oct 25, 2014

You are likely running into two simultaneous issues:

1) To keep the cost of the electronics down, wiring, complexity, etc., usually indicator LEDs are "multiplexed". What this means is that many LEDs are driven by a few lines and though they may look like they are on all the time, the "duty cycle", i.e. percentage of time they are really on may only be 10% They may be driven at a higher current than they can accept when driven continuously, but they are still not as bright as when on all the time. When you are looking at bar graph displays and similar complex displays on a mixing console, this would almost definitely be the base. Single indicators could be on all the time, but without taking it apart, would never know.

2) Wide angle versus narrow angle LEDs. LEDs in mixer boards would likely have LEDs with somewhat wide emission patterns so they can be clearly seen from any angle. Displays such as numbers, graphs, etc. will generally have very wide viewing angles. The "brightest" indicator style LEDs are generally considered bright as they have a narrow emission angle. I.e. they concentrate the small amount of light they put out into a small "area". If you are looking from within that angle, they look very bright ..... and of course dim outside it.

I would expect most usage is indoors, but perhaps giving feedback for "outdoor" units would be listened to. Just be prepared to pay more money.

Semiman

How bright can LEDs in electronics be?

TheMAXX

Newly Enlightened

Norm

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RoGuE_StreaK

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TheMAXX

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DIWdiver

Flashlight Enthusiast

TheMAXX

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DIWdiver

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SemiMan

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