I'm the Front-of-House Engineer for a youth ministry that does a lot of mission trips. Most of our trips have a band, a drama team, and a spoken message, and so we have a portable sound system to accommodate that. Over many years, we've improved that system so that we now have:
For #2, I'm pretty sure I want an array of horns. Horns for efficiency, on top of having more power available from the battery than I can get from a 14-AWG extension cord, and an array to control the dispersion pattern. Past that, I don't really know. I've thought about plane arrays and line arrays, and whether to give all the drivers the same full-range signal or progressively lowpass them as they get farther from center so that the total radiating area increases with wavelength, but there's nothing that really jumps out at me as the way it ought to work. Or can a full-range horn be directional enough on its own to not need an array? Is it already too directional for some venues and thus need a second one to expand the effective audience? In any case, whatever this thing ends up being takes DC power directly from the batteries, and a line-level input through a transformer so I don't have to worry too much about keeping the ground references straight.
For #3, I'm not really sure what to do yet. It probably depends on what I settle on for #2. Maybe a large-ish, thin array will be enough visually to command two people, and then be easy with two to mount on a stand? Or maybe it can have its own stand built in? Maybe I can design it to plant the bottom and then tilt up with one person? I thought briefly about a telescoping stand with block and tackle, but that's probably too complicated. In any case, it does have to send most of its energy over the top of the front couple of rows so that the back can still hear.
If it uses a lot of drivers, they'll have to be somewhat cheap, which means they might not sound all that great on their own. Some problems can be corrected with EQ (which can eat up some headroom); others just need to swap drivers.
Is this even reasonable? Is there a better way to do it? What do you guys think? I've seen a little bit of theory, but I've never actually done this, so it's definitely going to be a learning experience at any rate.
- One 55-pound, double-sided, 6-unit rack box (effectively 12-unit if you're good at playing tetris inside) for a remote-controlled digital mixer, power strip/conditioner, 2x3000W class-D power amp (peak power into 4 ohms), and some other accessories
- One 40-pound bag for various stands and cords
- Two 60-pound 8-ohm two-way speakers, rated to 400W continuous
- Requiring AC power at every venue
- Somehow, everyone seems to have it so far. I have no idea where some of them find it or how big the fuse is, but somehow they do and we haven't popped one yet.
- Not enough acoustic power in the audience
- I calibrated the attenuators to clip the amp and the mixer at the same time. Given that, I often run the meter all the way up outside and wish I had at least 10dB more. Not clipping, but right up there next to it.
- Awkward to setup and teardown
- They're the standard pole-mounted plywood-and-carpet bricks with only one handle, which is on the side. We put them up high so as to reach the back row without cooking the front.
For #2, I'm pretty sure I want an array of horns. Horns for efficiency, on top of having more power available from the battery than I can get from a 14-AWG extension cord, and an array to control the dispersion pattern. Past that, I don't really know. I've thought about plane arrays and line arrays, and whether to give all the drivers the same full-range signal or progressively lowpass them as they get farther from center so that the total radiating area increases with wavelength, but there's nothing that really jumps out at me as the way it ought to work. Or can a full-range horn be directional enough on its own to not need an array? Is it already too directional for some venues and thus need a second one to expand the effective audience? In any case, whatever this thing ends up being takes DC power directly from the batteries, and a line-level input through a transformer so I don't have to worry too much about keeping the ground references straight.
For #3, I'm not really sure what to do yet. It probably depends on what I settle on for #2. Maybe a large-ish, thin array will be enough visually to command two people, and then be easy with two to mount on a stand? Or maybe it can have its own stand built in? Maybe I can design it to plant the bottom and then tilt up with one person? I thought briefly about a telescoping stand with block and tackle, but that's probably too complicated. In any case, it does have to send most of its energy over the top of the front couple of rows so that the back can still hear.
If it uses a lot of drivers, they'll have to be somewhat cheap, which means they might not sound all that great on their own. Some problems can be corrected with EQ (which can eat up some headroom); others just need to swap drivers.
Is this even reasonable? Is there a better way to do it? What do you guys think? I've seen a little bit of theory, but I've never actually done this, so it's definitely going to be a learning experience at any rate.
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I suspect KC is large enough to have professional sound companies. I suggest you discuss this with one. A large music store, a pro sound company/retailer, and so on. You mention weight more than once, so if that matters, then it affects your speaker choices. You do need the speakers in the air, highs do not go through people, the audience blocks them, so as a rule if a listener cannot see the horns, he cannot hear them. Built in stands? I am not aware of any, but who knows? I can't imagine playing anywhere that did not also have help in the form of strong bodies., to help set up speakers.
Batteries and inverters? Do you really do ministries out in the bush? You say you have been doing this for many years, and have not lacked power yet. SO is it really worth hauling around the extra gear for battery operation just in case? Can you not specify in your contract that so much AC power will be provided? Or in events that lack power, rent a generator.
With 6000 watts available, I can see that 800 watts of speaker leaves room to grow.
So discuss it with a pro. A sound company can sell you speaker systems, or just pay someone to assess your needs and make recommendations. Instead of starting out assuming you need a horn and an array, I think you need to start out defining the venue needs you face. What size houses and audiences, how loud do you need it to be, long and narrow venues like churches? Or short and wide like lecture halls. And so on.
Batteries and inverters? Do you really do ministries out in the bush? You say you have been doing this for many years, and have not lacked power yet. SO is it really worth hauling around the extra gear for battery operation just in case? Can you not specify in your contract that so much AC power will be provided? Or in events that lack power, rent a generator.
With 6000 watts available, I can see that 800 watts of speaker leaves room to grow.
So discuss it with a pro. A sound company can sell you speaker systems, or just pay someone to assess your needs and make recommendations. Instead of starting out assuming you need a horn and an array, I think you need to start out defining the venue needs you face. What size houses and audiences, how loud do you need it to be, long and narrow venues like churches? Or short and wide like lecture halls. And so on.
How big and area (wide and deep) are you trying to cover?
What are the brand and model numbers on the speakers and amps you have?
I think you're in for a fairly rough reality check if you think you can get 10dB more SPL from any system that is smaller, lighter, and easier to handle than a pair of common 2-way PA cabs.
The solution to your problem might be horn loaded speakers but they won't be smaller or lighter than what you have and proper deployment of them will be a lot more labor intensive.. think flown arrays.
What are the brand and model numbers on the speakers and amps you have?
I think you're in for a fairly rough reality check if you think you can get 10dB more SPL from any system that is smaller, lighter, and easier to handle than a pair of common 2-way PA cabs.
The solution to your problem might be horn loaded speakers but they won't be smaller or lighter than what you have and proper deployment of them will be a lot more labor intensive.. think flown arrays.
... Or at least something big and ground-stacked.
That said, modern active boxes are getting good. I'd audition some of the latest offerings from JBL, Yamaha etc and see what you think. You get built-in amps, processing, all that jazz, and they usually weigh less than your current speakers. Even a pair of QSC K12s might be an upgrade, and they're getting a bit old-hat.
An immediate, and very obvious improvement to your current setup would be to put another handle on the other side of the speakers.
Chris
That said, modern active boxes are getting good. I'd audition some of the latest offerings from JBL, Yamaha etc and see what you think. You get built-in amps, processing, all that jazz, and they usually weigh less than your current speakers. Even a pair of QSC K12s might be an upgrade, and they're getting a bit old-hat.
An immediate, and very obvious improvement to your current setup would be to put another handle on the other side of the speakers.
Chris
Lots of good points, Enzo, that I think need separate answers, so here we go:
I've been to Guitar Center in person. Their showroom has nothing loud that's not also a big, heavy pole-mounted brick. I've been to several websites (Sweetwater, Zzounds, etc.) and seen some better variety, but still the same problem.
Our venues are anything from grade schools to high schools to public parks to whatever our host/guide/translator/"manager"/bus-driver comes up with. He lives there, and our job is to give him credibility as "North American Rock Stars" that agree with him. So we basically do all the setup/teardown work ourselves, out of a 1980-some Blue Bird school bus. (the performers are also the roadies) Our last trip had something like 18 programs in 9 days; 2 of those days back-to-back had 5 programs each, all in different locations with the same gear. By the time we came back to the States, we had gotten it down to about 8 minutes between dumping the air brakes and the first note of a live show.
Sometimes, yes. A couple of years ago, we left them a 50-pound backpack system that includes:
Of course, with a 3-channel volume-only mixer driving telephone-quality bullhorns, this is definitely not a system to play live music on. So we bring the full portable system for that, which I described in my first post, and it's that one that I want to run an outdoor concert with on batteries. (I don't expect a reasonable-sized solar array to come anywhere near keeping up with that power requirement, so I'm perfectly okay with dropping that part.)
No contracts. I'm pretty sure the only agreement with the venue is a verbal one with our driver that we're not privy to, and we really don't know what we're working with until we get there.
This actually works pretty well, given the language barrier: he knows what we do and what we need, and we're good at making it work. I'm just looking for more flexibility to support that "business" model if you can call it that. (it's all free for the audience, which is usually in public anyway, and paid for instead by the performers, who in turn often raise support from friends and family back home)
With just those numbers, yes, but that's comparing peak-amp to continuous-speaker ratings, and I want some headroom for live transients. Besides, I'm already running the amp wide-open into those speakers while keeping an ear out for any signs of distress. They only get half of the amp's power rating anyway because of the impedance mismatch: Amp = 6000Wpeak into 4ohms = ~3000Wpeak into 8ohms, Speakers = 800Wcont at 8ohms.
I think what makes that work is that they really don't get loud for very long at a time. Maybe 5-10 minutes of full-volume music, knowingly driving the speakers beyond their rated power, and then the rest of the hour is basically two speaking mics: one for the message and one for the translator. Then a bus ride to the next venue. So they have lots of time to cool off before the next 10-minute surge. This would also be good for battery life because I'm not actually drawing the max power for very long.
That said though, we did end up renting some speakers for two shows on Big Corn Island, Nicaragua. They were rated to 300Wcontinuous, 2000Wpeak at 4ohms. For the first show, we were on a truck driving around the island playing live music while our host announced the second show in the gym/community center. (I was behind the truck, running sound as a passenger on a motorcycle.) I had the music just below clipping as usual, so it would sound good; and to catch people's attention, I had the announcement well above that. So...basically 12,000W total into 4000W rental speakers, for which we later paid extra to re-cone. (hard clipping like that delivers twice the amp's rated power, in a square waveform)
We've been everywhere, man. (cue Johnny Cash)
I've been to Guitar Center in person. Their showroom has nothing loud that's not also a big, heavy pole-mounted brick. I've been to several websites (Sweetwater, Zzounds, etc.) and seen some better variety, but still the same problem.
Our venues are anything from grade schools to high schools to public parks to whatever our host/guide/translator/"manager"/bus-driver comes up with. He lives there, and our job is to give him credibility as "North American Rock Stars" that agree with him. So we basically do all the setup/teardown work ourselves, out of a 1980-some Blue Bird school bus. (the performers are also the roadies) Our last trip had something like 18 programs in 9 days; 2 of those days back-to-back had 5 programs each, all in different locations with the same gear. By the time we came back to the States, we had gotten it down to about 8 minutes between dumping the air brakes and the first note of a live show.
Sometimes, yes. A couple of years ago, we left them a 50-pound backpack system that includes:
- A projector the size of three smartphones stacked up that plays movies from a micro SD card
- A rear projection screen that is held tight with tent poles and can therefore hang or lean anywhere
- A 3-channel analog mixer with 2 mics + line-in (volume only, no EQ or FX)
- Two lithium batteries (small enough for the airlines to be okay with them)
- Two bullhorn speakers (optimized entirely for efficiency and weight, so it's basically a telephone sound)
- A soccer ball and hand pump 🙂
Of course, with a 3-channel volume-only mixer driving telephone-quality bullhorns, this is definitely not a system to play live music on. So we bring the full portable system for that, which I described in my first post, and it's that one that I want to run an outdoor concert with on batteries. (I don't expect a reasonable-sized solar array to come anywhere near keeping up with that power requirement, so I'm perfectly okay with dropping that part.)
No contracts. I'm pretty sure the only agreement with the venue is a verbal one with our driver that we're not privy to, and we really don't know what we're working with until we get there.
This actually works pretty well, given the language barrier: he knows what we do and what we need, and we're good at making it work. I'm just looking for more flexibility to support that "business" model if you can call it that. (it's all free for the audience, which is usually in public anyway, and paid for instead by the performers, who in turn often raise support from friends and family back home)
With just those numbers, yes, but that's comparing peak-amp to continuous-speaker ratings, and I want some headroom for live transients. Besides, I'm already running the amp wide-open into those speakers while keeping an ear out for any signs of distress. They only get half of the amp's power rating anyway because of the impedance mismatch: Amp = 6000Wpeak into 4ohms = ~3000Wpeak into 8ohms, Speakers = 800Wcont at 8ohms.
I think what makes that work is that they really don't get loud for very long at a time. Maybe 5-10 minutes of full-volume music, knowingly driving the speakers beyond their rated power, and then the rest of the hour is basically two speaking mics: one for the message and one for the translator. Then a bus ride to the next venue. So they have lots of time to cool off before the next 10-minute surge. This would also be good for battery life because I'm not actually drawing the max power for very long.
That said though, we did end up renting some speakers for two shows on Big Corn Island, Nicaragua. They were rated to 300Wcontinuous, 2000Wpeak at 4ohms. For the first show, we were on a truck driving around the island playing live music while our host announced the second show in the gym/community center. (I was behind the truck, running sound as a passenger on a motorcycle.) I had the music just below clipping as usual, so it would sound good; and to catch people's attention, I had the announcement well above that. So...basically 12,000W total into 4000W rental speakers, for which we later paid extra to re-cone. (hard clipping like that delivers twice the amp's rated power, in a square waveform)
We've been everywhere, man. (cue Johnny Cash)
- Open courtyard
- The central gazebo in a public park
- Concrete-and-tin gymnasium
- Long and narrow
- Short and wide
- Heavily reverberant indoors
- Outdoors on a small hill above a village
- Etc.
I was hoping for maybe a braced fiberglass construction or something like that. Make a wood mold and lay it up twice, for a stereo pair. I don't expect any manufacturer to offer that (for good reason, perhaps?), hence DIY. I was hoping that the good reason wasn't physical for the most part, but economic.
Your point about flying is definitely valid. Pretty much nobody we play for has even the structure to hang a fly system, let alone actually have one.
Actually, if the speakers *obviously* require two people to handle, I think that would be better than what we have now. Right now, we have a perpetual problem of one person trying to do it all by himself and nearly losing control with the speaker about 8 feet in the air. 😱 (and it's not the same person every time either)
Actually, we do have a pair of JBL PRX712's that were originally intended as portable mains, but are pretty much used exclusively as floor wedges now in our permanently-installed system. The PRX's are rated to 1500W each, compared to the 400W passive speakers, but "all that jazz" also includes a fairly aggressive limiter that works independently for each driver.
Understandably, that's to make them unbreakable by overdriving, but it also means that by the time you get to the volume that we typically use for music, the powered speaker is pretty much all tweeter while the seemingly-undersized passive 2-way with a massive amp still sounds like it's supposed to. Of course, I don't want to run it for very long at that power level or I'll melt the woofer's voicecoil, nor do we do that anyway just by the nature of the show.
That would definitely be an improvement, but these speakers are actually provided by our host organization and are used for lots of other things in the meantime. Unless the extra handle were recessed like the original, I think it would get in the way for some of their other uses. We could bring our practice speakers, already modified, but they're actually smaller and we'd have to pay that much extra for luggage on what effectively amounts to a bunch of personal flights on the same credit card.
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