Posted in education
on August 2, 2017 4:03 pm EDT
A Design Balancing Act
A look at two legs of the larger sanctuary sound tripod that deserve more attention.
When it comes to church sound, much of the focus in recent years has been on sound systems, and more specifically on how those systems’ coverage patterns can keep sound on seats and away from reflective surfaces. Technological advances like beam steering and columnar arrays have significantly improved the sound inside sanctuaries and other areas of houses of worship. But the attention that these solutions have received, as deserved as it is, can cause those concerned with the quality of church sound to overlook two other domains that are just as critical to quality audio, if not more so.
Acoustics and noise control are distinct areas of concern for house of worship (HOW) sound, and form two important sides of what ought to be a tripartite approach to sanctuary sound. “There are three primary areas that concern sound in a space and the electro-acoustical one—the sound system—is one of them, but the other ones don’t get the attention they should,” observes Dennis Paoletti, principal at Paoletti Consulting, a Bay Area acoustical consultancy that has many churches in its portfolio. “What we’re looking at are the acoustical properties of the space itself—the room acoustics—as well as the sound isolation, and noise and vibration control. And we’ll look at those in the context of the plan of the church; the type of structure it is—a cathedral, a former shopping center—all affects how and what type of acoustical and noise issues it can encounter.”Distinctions
Cameron Girard, an acoustical technician at Acoustics First, a consultancy in Richmond, Va., delineates acoustics and noise control as two sides of the same coin but with a critical difference. “Acoustics is about optimizing a space for sound quality and specific goals such as speech intelligibility and music performances,” he explains. “Noise control, on the other hand, is about minimizing the sounds you don’t want to hear in a space, such as the noise generated by HVAC and other mechanical systems.”
Acoustical analysis of spaces involves vetting a number of key and universally recognized criteria. “We’d look at things such as the reverb time of the room and the quality of reflections from the stage,” Girard says. “It would also be important to analyze the quality of the reverb itself; for instance, spaces used for acoustical instruments or that rely on choral music tend to have longer reverb times in the bass frequencies,” at or below 250 Hz for males.
When looking at noise control issues, the range of possible problem areas can be considerably wider, anything from mechanical systems like HVAC and plumbing to noise from adjacent areas such as cry rooms and classrooms to external noise from traffic. Structural vibrations can be especially vexing to track down and isolate, and that’s where acoustical expects will often interact with architects and mechanical engineers.
Sonora Fabric Wrapped Acoustic Wall Panels in a fellowship hall help reduce reverberation and distracting echoes. Shown here in both images, Second Presbyterian Church, Waynesboro, Va.
Acoustics First provided Sonora panels in a multi-purpose worship space, as well. One main objective was to control slap echoes.
Once identified—and that requires both measurements of the space and an experienced ear—acoustical problems are largely remedied using absorptive solutions: fabric, foam and fiberglass products, more and more of which are available off the retail shelf but which also have a wide array of bespoke solutions available, that deaden the space and stop or largely attenuate reflections. Absorptive solutions can be placed in a wide range of locations, anywhere from the ceiling to the backs of chairs and pews using upholstery. “You want to stop slap and flutter echoes with absorption, or use diffusion and diffraction to break up sound waves,” Girard says.
Location and choice of absorptive materials is an aesthetic decision as much as an acoustical one, and consultants will work with architects and interior designers to make sure that these treatments blend in as much as possible with a church’s décor. Another key point in this process is to avoid attenuating reflections so much that a space loses its liveliness. “That has to be considered in conjunction with the worship style a church uses,” says Girard. “Too little reverberation and it deadens music; too much and it affects speech intelligibility.”