Making an Acoustically Difficult Sanctuary Work: Cornerstone Family Church
Jul 6, 2006 8:00 AM
Conceived only 14 years ago by pastors Dan and Anne Berry, the non-denominational Cornerstone Family Church (Des Moines, Iowa) had lived with its audio system for more than 10 years, in spite of growth that expanded its sanctuary seating capacity to 1,100.
“Most of the equipment was eight to 10 years old,” says Terry McClannahan, Cornerstone Family Church director of operations. “The system had come together piecemeal. Some of the equipment had been purchased new; some of it was used. When pieces of the system failed, they were replaced, but without evaluation of the whole. Over the past couple of years, the system had become unreliable and generally very hard to manage technically, not to mention the fact that it wasn’t producing the sound we wanted.”
Music Minister Tina Williams can attest to that. “We lived with complaints from people who said that the sound was too loud, and complaints from people who said they could not hear,” she says. “I couldn’t hear the choir, the choir could not hear me or the instruments well, and they couldn’t hear each other.” Cornerstone Family Church’s basic musical setup consists of several vocalists, two bass guitars, two keyboards, trombone, B3 organ, and a six-piece drum set. Sunday services add a 70-person choir.
Early last year, Cornerstone Family Church began the process of a major upgrade for its sound system, which culminated in February of this year with the addition of a Yamaha M7CL-48 digital console from Harvest Productions in Kansas City, Mo. “We had heard that Harvest’s Peter Robinson had done some repair and upgrade work for an area church whose system wasn’t functional,” says McClannahan. “This church was very happy with Peter’s work, so we had him come in and evaluate our situation.” Later, McClannahan and others from the church would visit Harvest Productions in Kansas City for walk-through demos at local church sites.
The Room and the Sound System
“Our concern centered around the sanctuary itself,” says McClannahan. Cornerstone Church occupies what was once a warehouse, expanded over the years of its occupancy, but still retaining some of the limitations of the original structure. The sanctuary is almost perfectly rectangular, 180’x80’, with six pie-shaped seating sections. One hundred and ten acoustical wall panels and 43 flown banners in the room, plus a carpeted floor and cloth-covered seating, help tame the space. “What we needed to know was, ‘Can this room be made to work for us? Or, should we wait until we move into our new building to address the sound system issue?’”
Harvest’s Robinson performed some live testing using a TEF20 looking for long RT60 times and any reflection issues, and found the room to be adequate without any additional acoustic treatment. “We did find some issues in the speech realm,” he says, “but we were very confident in the Nexo speakers’ ability to carry in the space.” The new sound system is based around a Nexo FOH rig: four PS15s, two PS10s, three LS1200 subwoofers, one PS15 UTD processor, and one PS10-UTD processor. The Nexo loudspeakers are in a distributed mono setup: The PS15s are on the sides, the 10s are facing FOH, and the subs are in each corner and in the center on the main floor. All the loudspeakers are driven by Crown amplifiers, including four EAW SM109z floor monitors.
“Budget was a major player in the design,” says Robinson. “We had to choose a loudspeaker that would cover short-throw and still be able to cover the last rows. For this application, where there simply wasn't budget for short-throw and delay elements, the Nexo asymmetrical dispersion horn was the only choice. The finished system provided a +/-2dB across the seating area.”
Robinson tuned the PS10s first, then moved to the first pair of PS15s for tuning and time alignment. “The install crew hit the rigging spots near perfect,” he says, "so I didn’t have to work very hard to get the cabinets to overlap in the aisle. I then moved to the outside pair of PS15s. The obvious trick was to get the 10s and 15s to time align and EQ without perceiving a difference despite the difference in sizes of the woofers. There is no perceptible change of coverage as you move from the 10s to the first pair of 15s and finally out to the last pair.”
When we brought everyone into the sanctuary to hear the completed system for the first time Robinson comments, “It was very fulfilling to see the mixture of smiles and tears on the faces as they listened. The system was running at 115dB, with no complaints about it being too loud. They even captured video of the communion table skirt blowing in the ‘subwoofer breeze.’”
Cornerstone Family Church employs a full-time sound engineer who runs the Yamaha M7CL-48. Members from a team of six volunteers also fill in at FOH position for a total of some 20 hours a week of sound board work at the church. The M7CL, installed after the Nexo FOH system, “brought the whole system together,” says McClannahan.
“We’re pretty well-known in the community, so when other organizations are looking for advice on sound systems, they often visit our church,” says McClannahan. “Sometimes, Peter Robinson brings people through as well. Everyone is amazed at the clarity of this system.”
For more information, visit www.nexo-sa.com.
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