Tag Archives: System Building

A Weird LFE Routing Solution

Getting creative to obtain more bottom end.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

Want to use this image for something else? Great! Click it for the link to a high-res or resolution-independent version.

This is another one of those case studies where you get to see how strange my mind is. As such, be aware that it may not be applicable to you at all. I had a bit of a conundrum, and I solved it in a creative way. Some folks might call it “too creative.”

Maybe those people are boring.

Or they’re reasonable and I’m a little nuts.

Anyway.

I’ve previously mentioned that I handle the audio at my church. We’ve recently added some light percussion to complement our bass-guitar situation, and there was a point where our previous worship leader/ music director wanted more thump. That is, low frequency material that was audible AND a bit “tactile.” In any case, the amount of bass we had happening wasn’t really satisfying.

Part of our problem was how I use system limiting. I’ve long nursed a habit of using a very aggressive limiter across the main mix bus as a “stop the volume here” utility. I decide how loud I want to get (which is really not very loud on Sundays), set the dynamics across the output such that we can’t get any louder, and then smack that processor with a good deal of signal. I’ve gotten to a point where I can get it right most of the time, and “put the band in a box” in terms of volume. Drive the vocals hard and they stay on top, while not jumping out and tearing anyone’s face off when the singers push harder.

At the relatively quiet volume levels that we run things, though, this presents a problem for LF content. To get that extended low-frequency effect that can be oh-so-satisfying, you need to be able to run the bass frequencies rather hotter than everything else. The limiter, though, puts a stop to that. If you’re already hitting the threshold with midrange and high-frequency information, you don’t have anywhere to go.

So, what can you do?

For a while, we took the route of patching into the house system’s subwoofer drive “line.” I would run (effectively) unlimited aux-fed subs to that line, while keeping the mains in check as normal, and we got what we wanted.

But it was a bit of a pain, as patching to the house system required unpatching some of their frontend, pulling an amp partially out of a cabinet, doing our thing, and then reversing the process at the end. I’m not opposed to work, but I like “easy” when I can get it. I eventually came to the conclusion that I didn’t really need the house subs.

This was because:

1) We were far, far below the maximum output capacity of our main speakers.

2) Our main speakers were entirely capable of producing content between 50 – 100 Hz at the level I needed for people to feel the low end a little bit. (Not a lot, just a touch.)

If we wouldn’t have had significant headroom, we would have been sunk. Low Frequency Effects (LFE) require significant power, as I said before. If my artificial headroom reduction was close to the actual maximum output of the system, finding a way around it for bass frequencies wouldn’t have done much. Also, I had to be realistic about what we could get. A full-range, pro-audio box with a 15″ or 12″ LF driver can do the “thump” range at low to moderate volumes without too much trouble. Asking for a bunch of building-rattling boom, which is what you get below about 50 Hz, is not really in line with what such an enclosure can deliver.

With those concerns handled, I simply had to solve a routing problem. For all intents and purposes, I had to create a multiband limiter that was bypassed in the low-frequency band. If you look at the diagram above, that’s what I did.

I now have one bus which is filtered to pass content at 100 Hz and above. It gets the same, super-aggressive limiter as it’s always had.

I also have a separate bus for LFE. That bus is filtered to restrict its information to the range between 50 Hz and 100 Hz, with no limiter included in the path.

Those two buses are then combined into the console’s main output bus.

With this configuration, I can “get on the gas” with low end, while retaining my smashing and smooshing of midrange content. I can have a little bit of fun with percussion and bass, while retaining a small, self-contained system that’s easy to patch. I would certainly not recommend this as a general-purpose solution, but hey – it fits my needs for now.


More Features VS Groundwork

In this case, groundwork won: There wasn’t a compelling reason to lose it.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

Want to use this image for something else? Great! Click it for the link to a high-res or resolution-independent version.

The Video

The Summary

If you have significant prep that’s already done for one mixing system, you might want to avoid losing that effort – even if it would be to put a more powerful/ flexible mix rig into play.


Console Envy

When it comes to sound quality, any console capable of doing the show will probably be fine.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

Want to use this image for something else? Great! Click it for the link to a high-res or resolution-independent version.

The Video

The Summary

Which console sounds best? The one with the features you need. If an inexpensive mixer has all the necessary features for your shows, spending more doesn’t have much of a point.


Monitor World – Is “More” Better?

Often, the answer is “nope.”

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

Want to use this image for something else? Great! Click it for the link to a high-res or resolution-independent version.

Monitor world is a PA system, just like FOH is a PA system. The only difference is that monitor world handles a few very small audiences, and FOH usually deals with one comparatively large audience. All the helpful AND problematic physics considerations are the same.

This being the case, the stage is yet another place where simply piling up more and more boxes (all doing the same thing) to get “more” can be counterproductive. A vocalist wants more vocal, but their monitor is already doing everything it can, so you add another box. Does it look impressive? Yes! Is it louder? Yes! Is it better?

Yea- er…well…wait a second…

What you very well might end up with is a different set of issues. If the singer isn’t precisely situated between the wedges, the wedge outputs arrive at different times. This means that all kinds of destructive phase weirdness might be happening, and that can lead to intelligibility issues. The vocal range is very easy to louse up with time-arrival differences, and a sensation of “garble” can lead to a player wanting even MORE monitor level in compensation. In that instance, you haven’t actually gotten anywhere; Monitor world is louder, but it’s not any easier to hear in the information-processing sense. You also have greater effective loop-gain with that extra volume rocketing around, which destabilizes your system.

Plus, the low-frequency information still does combine well, which can lead to a troublesome buildup of mud. This goes double for everybody who’s off-axis (and that’s probably just about everybody who isn’t the intended audience of those wedges). That makes them want their own mixes to be hotter, which compounds all your problems even more.

And, of course, there’s even more bleed into FOH.

The brutal reality is that, for any single sound that a given player needs to hear, that signal will always sound better coming from a single box that “can get loud enough.” More wedges (all producing the same output) can only combine less and less coherently as you add more of them.

“But, Danny,” you protest, “you’ve done dual wedges for people. You’ve even rolled out some really excessive deployments, like the one in the article picture. Who are you to tell folks not to do that kind of thing?”

Fair point! In response:

1) It’s because I’ve tried some strange monitor solutions that I can say they weren’t necessarily improvements over simpler approaches.

2) Sometimes you do things that look cool, accepting that you’ll have to deal with some sonic downsides as a result.

3) Just because you’ve piled up a bunch of wedges, it doesn’t require you to put the exact same thing through each enclosure. Somebody might have two boxes in front of them, but one might be for vocals only and the other for instruments only.

With some bands, especially those who are naturally well balanced and don’t need a ton of monitor gain, the extra fun-factor and volume bump can trade off favorably with the coherence foibles. As the rest of this article indicates, yes, I am in the camp that says that a single box will always “measure better.” However, there’s more to life than just “measuring better.” If you have some room to compromise, you can be a little weird without hurting anything too badly.

Audio is an exercise in compromise. If you know what the compromise factors are, you can make an informed judgement. If you know that throwing a bunch of boxes at a problem might cause you other problems, then you’ve got more knowledge available to help you make the right decision for a fix.


You Don’t Just Need A Bigger Amp

Headroom is a holistic thing. If you run out of it in one place, getting more of it somewhere else isn’t enough.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

Want to use this image for something else? Great! Click it for the link to a high-res or resolution-independent version.

The Video

The Script

Let’s say that an audio human has a mixing console that’s feeding a loudspeaker system. (That makes sense, right? Most of us do that a lot.) This loudspeaker system is nifty because it’s magic. It never clips. The only limit on output is how much voltage the console can deliver.

The weird bit is that the console can’t really swing much voltage at its outputs. It clips at a peak of 1 volt. Another weird thing is that the console doesn’t have any inboard mic pres. Those are separate. (I know this is really strange, but I’m trying to make a point.)

Our aforementioned audio human just happens to have a mic pre that also reaches its maximum output at a 1 volt peak. They connect a signal source to the preamp, crank the pre until it’s just barely under clipping, set a fader at 0 dB, and…it’s not loud enough.

So, what do they do?

If you said, “They need a console with more output capability,” you’re exactly right.

It wouldn’t make any sense to buy a mic pre with more output, right? If the console output clips at 1 volt, what good does it do to have a mic pre that will deliver 12 volts into the console? You can drive the signal to the mix outputs a lot harder, but all that gets you is more distortion.

Obtaining and connecting an upstream device with more output is kinda absurd, frankly. It’s not a solution at all. The console output is the limiting factor.

But here’s the thing.

People take this actually non-sensical approach with amps and speakers all the time. Some of the confusion is understandable. Amplifier and speaker power ratings aren’t necessarily intuitive, for one, and passive speakers don’t have level meters as a rule. There’s also all the complexity involved with trying to describe the limits of a multi-device speaker enclosure with a single number.

I get that there’s nuance involved here.

But here’s the thing. Speakers, like everything else, have a maximum undistorted output point. It’s a peak level – a point beyond which there is no more “instantaneous” sound pressure to be had. If you have, say, a loudspeaker that can handle a peak input of 1000 watts, and an amplifier that can put a 1000 watt peak input through that box…you’re there. Your system is maximized. Any more available amplifier power is wasted on both driver distortion AND the chance that you might wreck your speaker.

But people see those nasty little clip lights on their amps, and think: “Gosh, I need to buy a more powerful amplifier!” They get obsessed with headroom, but in this compartmentalized way that only involves the amp.

Actually, unless the amp’s peak (NOT CONTINUOUS – PEAK)…unless the amp’s peak output is half (or less) of the speaker’s maximum peak rating, you do NOT need a larger amp. Getting a more powerful amplifier only gets you more headroom in the amplifier, when what you actually want is more headroom throughout the entire system output section.

What you need is a speaker that gets louder for the same amount of input. Or a bigger amplifier AND a speaker that can handle the additional power. Or just “more PA” in general – although that’s a whole other can of worms in itself.


Baskets, Bees, and Flies

Quality generally beats quantity.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

Want to use this image for something else? Great! Click it for the link to a high-res or resolution-independent version.

Sometimes, more IS more. It doesn’t matter how nice your mic cables are if you don’t have enough of them. If the show absolutely requires 24 channels, and you have a console with 16 really amazing channels…well, you’re still short by eight.

Yet, there are still plenty of instances where “a handful of bees is better than a basket of flies” (as Moroccans might say).

For instance, some folks are really hung up on the idea that a “main” PA speaker should be built around a 15″-diameter low-frequency driver. The idea is that bigger is better, but that’s not always so. Given a choice, I’ll take a good box built around a 12″ cone over a mediocre offering constructed around a 15. A well-designed 12 can be kinder to the vocals, because the cone driver is better at “playing” higher and covering the range that a small horn-driver can’t quite reach down into. Sure, the 12 probably won’t go as low, but if you want to be “loud” below 100 Hz you’re going to want subwoofers anyway. (For the record, I would never turn my nose up at a perfectly decent box that used a 15 or two.)

Also talking about speakers, there are people who believe a PA with more boxes is superior to a rig with fewer. The problem is that you have to take deployment into account. If you already have the necessary horizontal and vertical coverage happening, more boxes just act to cause more interference problems. The system looks cool because it’s bigger, and it gets louder because there are more boxes, but it doesn’t actually sound better. It might even sound terrible with all that comb-filtering going on. Coverage is sort of like what The Mad Hatter said to Alice: “When you get to the end, stop.”

This applies to bands too, especially when it comes to vocalists. One really brilliant singer with one mic is almost always light-years better than a whole group of vocalists of questionable quality. Beyond the basic aesthetics, not-so-hot singers tend to require a lot more gain to be heard (because they usually haven’t developed much vocal power), and that can easily lead to a system being run on the knife-edge of feedback all night.

…and speaking of people, how about crew-members? Any day of the week, and twice on Sunday, I’ll gladly take one knowledgeable, pleasant, and punctual helper over 15 punters who are late, surly, and have no idea what’s going on.

Tossing more and more junk at a problem rarely fixes the problem. You might eventually smother your issue or manage to distract from it, but the bugbear is still sitting beneath the pile. Applying a sufficient fix, on the other hand, works very reliably. There are times when you need “more.” There’s no getting around that. However, it’s important to avoid using “more” as a substitute for having what will actually do the job effectively.


Basic Power Distro Pointers

It’s all about impedance – either to ground, or to the load.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

Want to use this image for something else? Great! Click it for the link to a high-res or resolution-independent version.

Power distribution is a huge subject in concert production, and there’s no way for me to truly do it justice here. Especially when you get into the electrical supply issues for big shows, the topic can get pretty hairy.

Of course, we’re talking about small shows, so that makes things easier. Even so, please be aware of two major points:

1) Handling electricity correctly is absolutely critical to life and safety. Don’t take anything I say and run off towards some sort of homebrew, half-baked solution that can get someone killed. Making something in your garage to fix one problem is very likely to expose you to some other – potentially lethal – problem.

In fact, there’s the first pointer for small-venue power distro: If you made it yourself and you’re not an actual electrician, it doesn’t belong in the mains-power chain. If you ARE an actual electrician, it still might not belong in the chain. If you can’t buy it in an assembled form from a reputable vendor, plugging it into the wall is probably a bad idea.

2) This is not some sort of exhaustive discussion about everything that can possibly go wrong (or right) with power. This is just a few points that I’ve found helpful over the years.

Impedance To Ground Should Be As Low As Possible

A valid connection to ground is imperative for safety. Removing or bypassing the ground connection to “get on with the show” creates a situation where the impedance to ground is effectively infinite. That’s a very, very, VERY bad thing. If you don’t have a reliable, permanently attached, and code-compliant connection to ground, there’s no reason to go any further. Keep your power disconnected until that problem is fixed.

Electricity is very reliable about following the path of least resistance to a 0-volt reference point, that is, “ground” or “earth.” Solid, low-impedance connections to ground are a kind of insurance against accidents. If, say, a piece of equipment suddenly suffers a fault where the case becomes “hot,” a sufficiently low-impedance connection to ground allows a large current to flow across the connected supply circuit. This doesn’t seem helpful, until you realize that large currents are what trip breakers. The (hopefully) enormous surge pops the breaker or blows the fuse, in an effort to prevent people from dying.

An unreliable or absent connection to ground means that YOU may suddenly be the path to ground with the lowest impedance. Such a condition may end poorly for you.

Impedance To Ground Should Be Equal For Everything

Actually getting this exactly right is pretty close to impossible, however, it’s something to consider if you’re having a stubborn hum or buzz problem.

The issue for us audio humans is that our gear all gets connected together in some way. Although this interconnection doesn’t directly involve mains power, the connections to the main power service are definitely a factor. If you’re in the very common situation of the mixing console and other control gear being powered from a different outlet (and, very possibly, a completely different circuit) than the gear “on deck,” different pieces of gear can have multiple paths to ground. If the available pathways have impedances that differ significantly, current can end up flowing back around the various electrical junctions involved.

(Buzzzzzzzz…)

Since good, low-impedance connections to ground are critical to safety, one solution to this conundrum is to maintain connectivity to ground while using the fewest outlets and circuits practicable. For instance, getting an offending device to use the same circuit as non-problematic devices may help. You have an even better chance if you can use the same outlet box. You must NOT overload an outlet or circuit in the process of trying to achieve quietude, however. Safety has to win all contests of priority. If safety requires that you use multiple outlets and circuits, and you end up with some noise, you just have to live with it.

Resistance To Load Should Be As Low As Possible

Wire has resistance. It may be very low, but it is definitely not zero. Resistance increases in proportion to wire length, and increases in inverse proportion to wire cross-section. In other words, 100 feet of high-gauge (thin) wire resists current more than 1 foot of low-gauge wire.

Resistance causes electrical power to be wasted as heat, and causes noticeable voltage drops across long runs of supply cable. Cable offering too much resistance for the application can overheat under heavy use. This can cause a short, or even a fire.

So, very simply, use the shortest length and lowest gauge of mains power cabling that you can. Keep in mind that everything you connect in series is adding to the length of your run; The 15-foot pigtail on that power-strip counts!

Also, remember that any power cord in direct connection to the wall MUST be rated to carry the entire load that might be present on that connection. “Branches” to individual devices down the line can use lighter-gauge cable, because that single cable doesn’t have to manage the full load on the circuit. The feed to those branches, including any power strip or multitap involved, must be capable of safely operating with the full wattage of the circuit flowing across it. (Speaking generally, “14/3” electrical cable is sufficient for most small-venue power distribution applications. Going down to 16/3 is fine for branching from a multitap, but avoid using that cable for the direct run from the wall.)


As I said, this isn’t everything there is to know about power distro. However, you might find these tips to useful as you go along.


A Monitor Layout For A Rock Show

Sometimes you’re thinking about audio, and sometimes not.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

monitorsWant to use this image for something else? Great! Click it for the link to a high-res or resolution-independent version.

The picture attached to this article is an important reference point for the text. What you’re looking at is a scale drawing of the stage and monitor rig for the Sons Of Nothing: Clarity 10th Anniversary show.

So…why did it all end up like that?

The first thing that drives monitor placement is the stage layout – or, more precisely, where the actual players are going to be. In general, what we want to do with wedges comes down to one, simple rule: We want the loudspeaker output to hit whoever is supposed to be listening to it, while hitting as little of anything else as possible.

Of course, that rule gets bent (or simply taken outside and used for target practice with heavy artillery and wiffle bats) for various reasons, but it’s the starting point.

Down front, the plan was to have up to three people in play at any given moment. A guitarist downstage right, a solo vocal or solo guitar downstage right center, and a bassist parked down center. The down left riser was a dedicated space for a separate “keys and guitar” world. Center right was to be the land of woodwinds.

Upstage was split because of a need to run video. Sons Of Nothing uses projection as a key part of the concert, and in this case, front-projection was the order of the day. That meant that we needed a clear shot for the projector to fire “through” the band and onto the back wall. To get that open space, we put the drum riser off to the stage right side, and the backup-vocal riser went the opposite way.


Now, with the rule that I stated above, the natural inclination would be to always get a loudspeaker delivering a foldback mix as close to the players as could be physically managed. That’s not a bad rule of thumb. In fact, that’s a huge advantage of in-ears; You get to put the monitors so close to the player that they are partially inside their head, and only deliver usable output to that musician.

But an important realization is that live-sound is not actually about the best sound, as divorced from everything else. Rather, what we’re trying to do is create the best show, which is a holistic exercise.

Hence, the three downstage wedges were set on the floor, rather than up on the deck. The difference in distance was negligible, but a couple of very nice advantages were gained. Advantage 1 was that the loudspeakers no longer had as much physical contact with the riser, so they didn’t transfer as much vibration to the stage. Advantage 2 was that rather more of the main riser was available for actual people and the things they need to have to play well – like guitar-effect pedal boards.

A natural tendency is to set a player’s wedge such that it’s centered in front of them. In most circumstances, this is a reasonable idea. With a mono mix, most people like getting the output into both ears equally. There’s a problem, though, when keyboards enter into the equation. Physically, they’re pretty big and solid, and thus are very good at blocking the oh-so-critical “intelligibility frequencies” from a loudspeaker. Plus, keyboards can’t hear. It’s waste of output to fire a wedge into the bottom of a keys setup.

That’s why the keys wedge is off to the side. That placement allowed the sound from the drivers to have a clearer path to an actual human ear. A big help with making that placement work was the use of supercardioid-pattern microphones. Their pickup null points are at an angle to the rear of the mic (rather than straight back) and they have a tighter pattern in general. That helps significantly in being able to get enough output from a box that’s coming in from a diagonal. (With supercardioids and a monitor directly in front of the player, having the mic parallel with the floor helps to get that wedge firing into the least sensitive areas of the pattern.)

I would have liked to have put the keys wedge on the floor, but I was worried that the necessary distance for a good angle would be too much of a tradeoff.


Talking about the upstage folks, it might seem a bit weird that the backup-vocal wedge was set so that the riser partially blocked its output. There is an explanation though. First, I was concerned about chewing up real-estate on that platform, because there wasn’t much to go around. Second, some blockage from the riser was actually helpful. Plenty of sound that needed to get to the vocalists’ ears could still get there, with “splash” from the back wall mostly heading up into the acoustically treated ceiling. If the wedge had been up on the riser with the singers, there would have been a lot more spatter in general, and a lot of those reflections might have headed directly for the vocal mic in keyboard land.

The drumfill was an exercise in compromise. From a purely audio-centric perspective, it would probably have been best to to put things on the stage-left side of the drummer, with the full-range wedge off the sub and pointed upwards. The backup vocalists wouldn’t get blasted with the drummer’s monitor mix, and excess spill would go up into the ceiling. Unfortunately, logistics got in the way of this. Most of the square-footage on the drum riser was needed for…you know…drums, and so the “idealized” drumfill setup was too greedy for space. It also would have made it very hard, or maybe even impossible for the percussionist to enter from stage left as was planned. Stacking the drumfill on the left would have blocked the video.

So, a tall stack on the up-right corner was the solution.


One bit that I haven’t yet discussed is that lonely subwoofer that’s just upstage of center. What the heck is that?

Well, remember that down-center was the bass-player’s territory. As an additional wrinkle, no bass backline was brought in, except for a wireless rig. Such being the case, we needed to ensure that adequate low-end was produced for the folks on stage. Sonically, it would have been better to push the subwoofer downstage a bit (to reduce the time-arrival difference between the low-frequency information and everything else), but it seemed more important overall that it just not be in the way. So, I set the box flush with the drum riser, dialed the internal crossover for about 90 – 100 Hz, pulled the high-pass output to the down-center wedge, and the bassist ended up with a triamped monitor rig that could make some rumble without being run hard.

As far as I could tell, the overall setup was a success. Now, if only the woodwinds monitor hadn’t become unplugged at an unhelpful time…


How To Buy A Microphone For Live Performance

A guest-post for Schwilly Family Musicians

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

vintage_microphone-wallpaper-1280x800

From the article: “At the same time, though, a LOT of mics that are great for recording are a giant ball of trouble for live audio. Sure, they sound perfect when you’re in a vocal booth with headphones on, but that’s at least one whole universe removed from the brutal world of concert sound. They’re too fragile, too finicky, too heavy, their pickup patterns are too wide, and you can’t get close enough to them to leverage your vocal power.”


The whole thing is available for free, so go ahead and take a gander.


How Much Light For Your Dollar?

Measurements and observations regarding a handful of relatively inexpensive LED PARs.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

box_of_lightsWant to use this image for something else? Great! Click it for the link to a high-res or resolution-independent version.

I’m in the process of getting ready for a pretty special show. The album “Clarity” by Sons Of Nothing is turning 10, and a number of us are trying to put together one smasher of a party.

Of course, that means video.

And our master of all things videographic is concerned about having enough light. We can’t have anybody in the band who’s permanently stuck in “shadow.” You only get one chance to shoot a 10th anniversary concert, and we want to get it right.

As such, I’m looking at how to beef up my available lighting instruments. It’s been a long while since I’ve truly gone shopping for that old mainstay of small-venue lighting, the LED wash PAR, but I do take a look around every so often. There’s a lot to see, and most of it isn’t very well documented. Lighting manufacturers love to tell you how many diodes are in a luminaire, and they also like to tell you how much power the thing consumes, but there appears to be something of an allergy to coughing up output numbers.

Lux, that is. Lumens per square meter. The actual effectiveness of a light at…you know…LIGHTING things.

So, I thought to myself, “Self, wouldn’t it be interesting to buy some inexpensive lights and make an attempt at some objective measurement?”

I agreed with myself. I especially agreed because Android 4.4 devices can run a cool little Google App called “Science Journal.” The software translates the output from a phone’s ambient light sensor into units of lux. For free (plus the cost of the phone, of course). Neat!

I got onto Amazon, found myself a lighting brand (GBGS) that had numerous fixtures available for fulfillment by Amazon, and spent a few dollars. The reason for choosing fulfillment from Amazon basically comes down to this: I wanted to avoid dealing with an unknown in terms of shipping time. Small vendors can sometimes take a while to pack and ship an order. Amazon, on the other hand, is fast.

The Experiment

Step 1: Find a hallway that can be made as dark as possible – ideally, dark enough that a light meter registers 0 lux.

Step 2: At one end, put the light meter on a stand. (A mic stand with a friction clip is actually pretty good at holding a smartphone, by the way.)

Step 3: At the other end, situate a lighting stand with the “fixture under test” clamped firmly to that stand.

Step 4: Measure the distance from the lighting stand to the light meter position. (In my case, the distance was 19 feet.)

Step 5: Darken the hallway.

Step 6: Set the fixture under test to maximum output using a DMX controller.

Step 7: Allow the fixture to operate at full power for roughly 10 minutes, in case light output is reduced as the fixture’s heat increases.

Step 8: Ensure the fixture under test is aimed directly at the light meter.

Step 9: Note the value indicated by the meter.

Important Notes

A relatively long distance between the light and the meter is recommended. This is so that any positioning variance introduced by placing and replacing either the lights or the meter has a reduced effect. At close range, a small variance in distance can skew a measurement noticeably. At longer distances, that same variance value has almost no effect. A four-inch length difference at 19 feet is about a 2% error, whereas that same length differential at 3 feet is an 11% error.

It’s important to note that the hallway used for the measurement had white walls. This may have pushed the readings higher, as – similarly to audio – energy that would otherwise be lost to absorption is re-emitted and potentially measurable.

It was somewhat difficult to get a “steady” measurement using the phone as a meter. As such, I have estimated lux readings that are slightly lower than the peak numbers I observed.

These fixtures may or may not be suitable for your application. These tests cannot meaningfully speak to durability, reliability, acceptability in a given setting, and so on.

The calculation for 1 meter lux was as follows:

19′ = 5.7912 m

5.7912 = 2^2.53 (2.53 doublings of distance from 1m)

Assumed inverse square law for intensity; For each doubling of distance, intensity quadruples.

Multiply 19′ lux by 4^2.53 (33.53)

Calculated 1 meter lux values are just that – calculated. LED PAR lights are not a point-source of light, and so do not behave like one. It requires a certain distance from the fixture for all the emitters to combine and appear as though they are a single source of light.

The Data

The data display requires Javascript to work. I’m sorry about that – I personally dislike it when sites can’t display content without Javascript. However, for the moment I’m backed into a corner by the way that WordPress works with PHP, so Javascript it is.


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