Those of us in the world of church audio tend to focus most of our efforts on our large, sophisticated systems in our main sanctuaries. This makes some sense — not only do we serve the lion’s share of our congregation with these primary systems, but because the big, main systems are larger and more complex, they require more attention. But we still need to put time, effort, resources, and thought into our less sophisticated systems. And for smaller churches, the main system may qualify as “less sophisticated,” and may reside in a rented space.
Frequently, these rented spaces are the “multi-purpose” rooms maintained by high schools, middle schools, and even elementary schools. Their typical form-factor is like that of a gymnasium, sometimes with a stage. And, of course, numerous large churches maintain their own such multi-purpose spaces. They’re used for children’s and teens’ ministries and to host church league basketball and as concert halls for touring artists who haven’t quite hit the big time yet. As one might expect, the sound quality of these less sophisticated spaces may not quite reach the high expectations we have for our main sanctuaries, but it doesn’t have to be that way. Just a little thought, planning, and execution can substantially improve our audio quality in multi-purpose spaces. Let’s see what we can do.
Beyond the ‘Gymnasium’ Sound
As multi-purpose spaces tend to be gymnasium-like most of the time, they also tend to be shaped like a box most of the time, and boxes are pretty much the least acoustically friendly spaces there are. I would even say that they viciously (and maybe even consciously) fight against our efforts to make music and speech sound good. But we do have some weapons, strategies and tactics available to help us in our battle. Some multi-purpose spaces have reasonably good acoustical properties. One would think that if a room is designated to host both church league basketball and church services, then acoustics would be considered from the outset. Gymnasiums don’t have to have hard, reflective surfaces in every direction, and in some cases, plenty of absorption is deployed from the very beginning. If not, however, it’s certainly plausible to get some absorptive panels up after the fact. Diffusion is also very helpful, but if you’re going to spend money on only one kind of after-market acoustical treatment, absorption is probably going to resolve more issues for you.
A second major solution beyond acoustics is the choice of an audio system that does the job well. I would submit that a first consideration should be the size of the P.A. Bringing in an overpowering P.A. producing more SPL than necessary will also produce more reflections than we want. That said, deploying a high-quality system is smarter than deploying a “high quantity” system. A line array that allows more control of “throw” will help reduce a lot of reflections. Directionality is key here — and that’s nothing new — point the speakers where you want the sound to go and avoid pumping SPLs where you don’t want it. Steerable systems are even better in this way. If steerable line arrays are beyond your budget, you can still be smart about how you deploy the speakers that are in your budget. Avoid directing SPLs into reflective surfaces, which not only add to the reverb soup, but can create some unpleasant phase incoherencies. Pointing speakers toward reflective surfaces diminishes the amount of control you have over where that energy ends up going. Speaker placement is very important.
As we know, higher frequencies are more directional, and hence it’s easier to point them the way we want them to go. But as we move downward in the frequency spectrum, sound begins to become more and more omnidirectional, and the spherical dispersion of lows is an enemy of clarity and control. Luckily, it’s plausible to set up directional subwoofer arrays with a little math and know-how. Again, directing SPL energy where we want it (and more importantly away from where we don’t want it) goes a long way toward reducing out-of-control reflections in our space.
The Silent Stage
I’ve long been an advocate for the concept of a silent stage. It’s impossible to accomplish a perfectly 100% silent stage, but lowering stage volume is another reduction in the amount of SPL bouncing around our boxy multi-purpose room. Start out by attempting to reduce drum volume. As a guy who occasionally sits down behind the kit, I completely understand why most players prefer genuine acoustic drums. They feel more natural to play, and frequently sound better than electronic drums. Note that I avoided stating that they always sound better than electronic drums. Over time, drum samples have continued to improve, and more importantly, the drum pad controllers we use to play them have also improved substantially. A quality sampled drum kit, when properly mixed, can actually sound a LOT better than a poorly mixed acoustic kit that hasn’t been tuned properly.
If electronic drums are not in the cards, isolating the drum kit inside a plexiglass terrarium can be very helpful. Even just getting the kit behind plexiglass shields can be helpful. In the domain of guitars and basses, it’s very nice to use modeling or amp isolation away from the platform. But even failing this, we can still keep SPLs down by directing combo amp energy away from the congregation, and possibly even into an absorptive panel. One final way to reduce stage volume is to eliminate or at least limit the number of monitor speakers. I’ve heard many services during which the monitors were as loud or louder than front of house, and that can add a lot of SPLs to the energy bouncing around our box-shaped gym.
More Proven Techniques
It would be easy to conclude that additional room absorption is implausible in a portable-church scenario. But that’s simply not true. The use of drapery with convention hall-style curtain rods could at least eat up some high-frequency reflections, as could office-style gobos. Both solutions can be surprisingly portable. Another clever trick to increase absorption is using soft-upholstered chairs. A portable church with which I was formerly affiliated used 100% upholstered chairs with moderately thick foam — a great way to decrease reflections, particularly if our P.A. is properly directing (and restricting) its SPL energy exclusively into the seating area.
There’s no reason why box-shaped multi-purpose rooms should win the battle. If we can get some permanent — or at least semi-permanent — absorption and/or diffusion in place, we gain a little advantage. Deploying a proper-sized P.A. for the space adds another plus. And if we can direct SPL where we want it to go (and away from where we don’t want it to go), we gain even more advantage, as does leveraging cardioid sub arrays. Keeping stage volume under control is another goal. Add them all up, and we can achieve decent quality audio and win the battle against those nasty, box-shaped multi-purpose spaces. Let’s go fight!
John McJunkin is an adjunct professor at Grand Canyon University.
