When it comes to renovations, it can be harder to adjust the acoustical properties of a space—because you’re constrained by the architecture. A high, curved ceiling may be causing significant reflections that create intelligibility problems for the spoken word, but aesthetic considerations may preclude the use of such common acoustical treatments as absorbent “clouds” suspended above the sanctuary or panels attached to ceilings and walls. These kinds of situations can become so complex that most types of passive responses won’t be enough to solve the acoustical problems. John Storyk, a noted sound system designer, acoustician and principal at Walters-Storyk Design Group in upstate New York, recalls that his work on Central [Synagogue] in Manhattan required the use of an active electro-acoustical solution when the landmarked interior of the synagogue couldn’t accommodate passive treatments. In this case, a Lexicon LARES system was installed. An active-electronics approach, also employed by the Meyer Sound Constellation system, LARES uses microprocessors to, among other functions, control multiple microphones placed around a performance space that constantly “listen” to acoustical artifacts and then create phase-reversed versions of them that cancel them out.
It’s an expensive solution, but it underscores how the inventory of electronic solutions for acoustical problems has increased. For instance, small, steerable columnar arrays—slender and rigid lines of speakers generally attached to vertical roof-support columns—offer an esthetically unobtrusive way to focus sound locally in churches by bringing it closer to the seating areas and keeping energy off of reflective surfaces like walls and floors, and using digital delays to synchronize the arrival of audio from front to back of the building. The earlier, the better.
The best outcomes are those that are preordained, as a result of the acoustician and architect coming together before a building is erected. Christ Chapel Bible Church in Fort Worth, Texas, is an example of this all-too-rare but serendipitous occurrence. Architect Scott Martsolf and Chris Jordan, president and self-described “chief steward” of AV integration and systems design firm Electro Acoustics of Fort Worth, were able to confer before the church was constructed 10 years ago. Jordan spotted the potential for acoustical problems and suggested the consult with an acoustician, and Bill Johnson of Dallas-based Acoustic Design Associates was brought in. He suggested a Helmholtz resonator design for the sanctuary’s soaring dome, addressing both an aesthetic mandate and the acoustical issues that accompanied it.
Christ Chapel Bible in Ft. Worth. Courtesy of Chris Jordan.
“It was the church’s desire that when you enter, your eyes are drawn to the height of the ceiling,” says Jordan. “It’s a very worshipful feeling, and part of that effect is supported by the idea of using wood, a very organic material, to reinforce that feeling. But that kind of [sonically] reflective material in that much cubic volume [inside the dome] meant that the [sonic] energy would be hard to control. The sheer number of absorptive panels needed to address the situation would have been very costly and aesthetically dubious, since the sanctuary is well lit and the panels would be very visible.” Instead, the acoustician suggested the Helmholtz resonator solution, and an 18-inch cavity behind the ceiling, with variable spacing between the celling’s wooden planks and absorptive panels behind them. This configuration attenuated much of the sonic energy in the room but allowed enough to circulate to give the music a very live feel.