Posted in education
on June 30, 2017 9:54 am EDT
Demystifying Sound in Challenging Spaces
Houses of worship come in many shapes and sizes, and designing sound to fit them is one of AV's biggest challenges.
At Syracuse University’s 85-year-old Hendricks Chapel in Syracuse, N.Y., Renkus-Heinz columnar Iconyx Gen5 IC24-RN digitally steerable line arrays were mounted on each side of the proscenium. Image courtesy of DCI Sound.
The two main issues that churches generally encounter are outsized reflections/reverberation and problems relating to coverage. The first type of problem generally manifests itself when churches try to reconcile the very different (and often opposing) requirements of speech and music. The former demands as little reverberation as possible to achieve high intelligibility while the latter thrives on the warmth that ambient reflections can add to music.
Architectural details like the depth and width of the room (its interior aspect ratio), ceiling height, location of balconies, and interior coverings like carpeting or velour seats all contribute to the challenge of getting useful sound in a church.
This dichotomy becomes even more complicated for churches that have to employ both traditional liturgical music (think Gregorian chants) for which long reverb times are like gravy, and contemporary worship music, whose louder, more staccato nature is best served by short reverb times. The pastor then has to make himself or herself not only heard, but understood, in the middle.
The other kind of challenge has to do with getting a sound system to cover seating areas evenly and consistently while at the same time keeping that sound away from walls and other reflective surfaces (which add to the problems created by issue number one). This in particular is where the irregular interior architecture of many churches can underscore the fact that no single design or approach is exactly like another. Architectural details like the depth and width of the room (its interior aspect ratio), ceiling height, location of balconies, and interior coverings like carpeting or velour seats all contribute to the challenge of getting useful sound in a church. Here are a few tales of churches and designers facing these challenges and how they solved them.Fans of Good Sound
First West Church, in West Monroe, La., wanted to upgrade its PA system to be able to accommodate both traditional and contemporary music styles, so it could avoid having to bring in a rental PA for touring artists. At the same time, it also wanted to find a way to better cover the seating in its large fan-shaped, 1,800-plus-seat sanctuary, where the contemporary service uses both musicians and vocalists while the traditional service uses a 100-plus-voice choir and orchestra.
“The 180-foot wide and tall fan-shaped room was designed as a traditional-style building, so there were many architectural reflections, and few useful acoustic panels to minimize this,” states Gwin Edwards, president of American AVL in nearby Ruston, La.
Edwards decided on a NEXO GEO S12 sound system, a type they had used in other installations in the region, which enabled the church leaders to experience the system in a worship environment. But it was the configuration that was most critical to solving the church’s sound issues. The original system was a center cluster, supported with some left and right fill speakers that too broadly dispersed the sound in the space. With the NEXO system, Edwards designed a more formal L-C-R system that would provide both a balanced stereo image for music and a center speaker for intelligible speech. (Interestingly, the old system’s speakers were disconnected and left in place; Edwards says the cost of removing them and filling the 20-foot-wide soffits they occupied was neither technically warranted nor esthetically necessary. The old system’s amplifiers, however, were removed and repurposed elsewhere in the building.)
The 180-foot wide and tall fan-shaped room [at First West Church in West Monroe, La.] was designed as a traditional-style building, so there were many architectural reflections, and few useful acoustic panels to minimize this. - Gwin Edwards, President, American AVL, Ruston, LA
The new system’s 30 boxes, including eight RS18 Ray subs, are powered by 10 NEXO NXAmps. “Three arrays are setup as ‘stereo-plus-mono,’ so the music and effects can be routed stereo while vocals stay centered,” Edwards explains, noting that they used the NEXO NS-1 predictive-modeling software to position the boxes. “There are also side fills on the outside of the stereo arrays to provide ‘near-stereo’ fill to the extreme outsides, while maintaining sonic image. There are two cardioid sub arrays, in a stereo/left-right configuration, to beam-steer the bass energy more evenly across [the] room, instead of just down the center.”
The system solution was complemented with an acoustical one. The existing acoustical treatments in the church didn’t offer enough surface area and were only one-inch thick, which would barely cover an octave. Edwards replaced them with four-inch deep Perdue Acoustics Rockwool panels that are far more absorbent.
“Fortunately, as part of the latest system update, the church leaders told us to do whatever was necessary to correct the acoustics,” Edwards says. During renovation, he says they were able to notice the difference in the sound quality on the updated half of the room compared to the side that still had the old treatment. “It was easy to notice that all of the old echoes and excessive liveness were now gone on the newly treated side,” he recalls. “Once the other side and rear were completed, we were even more impressed with the room’s new acoustics.”
Ultimately, any useful solution will involve a combination of system hardware and acoustical treatments, Edwards emphasizes. “Finding the right balance between them is the trick.”