Every year, dozens of magazine articles are written in the church publishing world about audio systems and controls…with one glaring omission, which is regarding the most significant starting point – the shape of the space itself for sound. This “natural room acoustic primer” will address the basic concepts for consideration of both existing spaces and new construction.
The main reason for the reality of this omission is that – at least in the “church world” – AVL-A (Audio, Video, Lighting (Theatrical) and Architectural Lighting) companies have little to no control over the shape of the space, unless, of course, it’s a new building.
However, even with a new building, the norm in the church facilities world is for the AVL-A company to be brought in after the design is complete and typically even after construction has begun.
What this article will address are ways to evaluate the most ideal shape(s) of – and for – worship space with the caveat of the necessity of balancing the spoken word with musical worship. It may seem counterintuitive to begin with the least ideal spatial shapes for sound, but stay tuned.
Let’s be clear from the very beginning that construction costs of proper room acoustic shapes are NOT more expensive than “regular” building construction types. This is especially true when you consider that churches spend thousands of dollars in acoustic treatment (usually the wrong type and quantity and in the wrong places) with seemingly continual audio system upgrades/renovations in attempts to compensate for the initial poor shape of the room over the lifespan of the building.
When the initial natural acoustics of the space are bad, then you throw away (in no particular order) your bank account, your schedule, and your expectations because you’re at negative 100 trying to get to zero. And, in all likelihood, congregants will still complain that “the sound is bad.”
As a licensed architect specializing in natural room acoustics (i.e., before the power is turned on), these observations come from being involved in over 400 churches over the last 40 years from 30 seats to 300,000 seats across the world, spanning Greek Orthodox to Pentecostal churches and everything in between. This includes a year based in Rome, Italy, studying the natural acoustics of pre-electrical churches, as well as the natural acoustic qualities of ancient ruins.
From the first moment that we were able to “plug stuff in,” we’ve lost the knowledge of how the shape of spaces affects sound. I apologize in advance for the “commercial,” but on our website, there is an 8 minute video in which you will learn everything you need to know about natural acoustics in less than 3 seconds – just wait for “the sound of my voice” segment. If you’re really curious for a deep dive in this issue, then reference my book, “Soul Space: Ancient Realities in Post-Modern Worship Spaces” circa 2018.
Since hindsight is 20/20, perhaps the place to start is the least desirable shapes, since the vast majority of churches seem to be in this realm as most of our houses of worship clientele in our history have been existing spaces. By far, the two worst spaces are cube-like or round. While the actual cubic “volume” (length, width, height) of the space is an important metric (ideal is 400 cu. ft. per seat), the ceiling plane also factors into the shape of the space, as well as the floor plane(s) – flat, sloped, terraced, etc.
The two worst spaces are those that approach [1] a cube (length, width, height are similar) or [2] round (concave). Even more unfortunate would be some combination of the two.
The cube violates what I refer to as the “11th commandment” – Thou shalt not have parallel walls, walls, walls (or ceilings, for that matter).
A round space, or a pie-shaped space with a concave rear wall, produce an “acoustical racetrack” where the sound travels continually unimpeded around upon itself building energy in the worst way.
If you add a dome into the mix with either of these shapes, then it very quickly “goes off the deep end” to the point of no return.
So, what’s a building committee to do? If it’s a renovation project, then the space needs to be evaluated by a professional to design the proper wall and ceiling acoustic treatment (not just absorption, but also reflection) to overcome the room shape deficiencies. If we take the opposite of what we know to be the bad spaces, then non-parallel surfaces and convex curved shapes are desired for good natural acoustics.
If it’s a new building, then the job is much easier because the more effective the shape of the room is acoustically, then the less acoustic treatment is required, the more effective (and less expensive) the audio system will be – and more importantly – the easier it will be for paid staff and volunteers to be trained and operate it in efficient fashion.
Whether it’s an existing or a new space, the room shape goal is “non-parallel” if rectilinear elements and “convex” for any curvilinear elements, all with respect to ceiling, walls and floor. This can be accomplished in existing spaces with acoustical ceiling clouds (suspended panels from the ceiling) and “jagged” wall panels.
It is important to note that in any interior space, the vast majority of the initial acoustical absorption capability comes from the ceiling plane so that surface shape is critical. The next most impactful will be the side and rear wall treatments as generally speaking (uh, pun not intended), harder surfaces are desired near the sound source (i.e., the platform), with softer more absorptive materials further away.
The elephant in the room (again with the pun, sorry) is that the vast majority of church audio renovation projects do nothing to address room shape deficiencies – which, as we now know, has the most impact on the eventual congregational experience.
Yes, there are technologies that can “make your closet sound like your shower and vise-versa,” but they are expensive to install and complicated for the average church tech to operate.
Beyond that, the basic premise that [1] speaking (acoustically a closet for hearing every word) and [2] musical worship (acoustically a shower for lively vocal and instrumental sound) are both competing acoustical realities, it’s a delicate balance.
However, in the right professional hands, it’s actually very easy, especially when the initial focus is upon the various functional “experiences” desired by the church with corresponding designs for each experience in the very beginning of the project.
Whether it’s a new build or a renovation project, we accomplish this experience design alongside (paraclete) each church client in our interactive “Design Workshop Process,” which includes an AVL-A Designer/Integrator and a CM Construction Manager from the get go.
Kevin L. Callahan, AIA NCARB LEED-AP BD+C, is the founder of CALLAHANstudios soul space +361 experience architectural studio based in Scottsdale, Arizona, www.callahanstudios.com.
