Install of the Month
Nov 1, 2002 12:00 PM, Daniel Keller
As any seasoned systems contractor will tell you, visual design and sonic integrity are rarely players on the same team. Nowhere is that dichotomy more pronounced than when one is faced with the task of bringing a traditionally designed house of worship into the new millennium. Those long, reverberant spaces so beloved for choirs and pipe organs don't take well to modern amplification, and the result can become an exercise in futility.
But even as houses of worship go, the Preston Hollow Presbyterian Church in Dallas presented design engineer Steve Whittle and the Whitlock Group with more than the usual set of challenges. “The building and the space were kind of hard to work with,” says Whittle.
The space Whittle is referring to, the sanctuary, was part of a massive expansion and redesign at this 2,700-member church. The new, improved sanctuary is shaped somewhat like a modified cross, with generous amounts of glass in the walls and a concave ceiling some 30 feet high. “It was sometimes hard to understand what was being said in there, even before the sound systems,” says Whittle. Add to that the all-powerful decorating committee's decision to remove that pesky carpeting in favor of a tiled floor with a nice wide aisle, and you can almost taste the standing waves.
“The actual system design was done by Chris Cassell of Scott Riedel Associates in Milwaukee, and it was excellent,” Whittle says. “But when we were brought in as the contractors, the committee asked, ‘If there was anything you could change, what would it be?’ It was clear that they were prepared to take the system to the next level.”
The first thing the Whitlock Group suggested was replacement speakers in the main sanctuary, because the original speakers didn't present a pattern control. “Rooms like this one are designed for pipe organ and have reverb times of well over two seconds,” says Whittle. Speakers with tight pattern control were needed so they could point the sound at the seats and keep it off the walls and ceilings as much as possible.
“The other thing we found was that they had a bunch of old analog tie-lines going to and from the main sanctuary to the chapel and several other halls in the complex,” Whittle says. “These were really restrictive, especially because they had an 8-channel recorder in a little performing hall on the other side of the building but could only bring over one channel from any given room.
“We suggested that for a little more money, we could migrate from their present processing architecture over to Audia. When the system was originally designed, Audia didn't exist, but now we were able to show them what they could be capable of, and they were impressed. It has a lot more horsepower, and we were able to redesign the church's whole digital signal-processing [DSP] architecture; it enabled us to move from passive crossovers to biamped speakers in the main sanctuary, and they finally had enough DSP for individual mic EQs. It also got us Audia's networking capabilities and CobraNet, throughout all the rooms.”
The main sanctuary is outfitted with two 32-channel Allen and Heath consoles, one running a front-of-house mix and the other a custom broadcast feed for the local FM station. Microphones are mostly Shure UC systems and hanging condensers. QSC amplification and Renkus-Heinz C5s drive the sound.
“One of the things that's been interesting in this room is that because it's so live, timing is critical,” says Whittle. “With the ceiling so high and the speakers so far up, the CobraNet latency becomes a factor. The Audia system lets us turn off delay compensation to get the timing as short as possible in areas where an extra 12 or 15 ms created by CobraNet hops put us over the threshold where the sound came too late relative to the acoustical sound from the stage. CobraNet has advantages over other systems, but it does have more latency. Fortunately, Biamp had foresight to allow the user to control that.”
The new system also helps integrate the church's many media functions. Because all the processing is done in Audia, all rooms are now fully integrated. Any point in the system can be accessed by PCs in the broadcast booth and one of the halls. “But because the whole system hangs off the house LAN, anything can be controlled by a laptop with the Audia software, from almost any room in the grounds,” Whittle says.
Of course, the various rooms and halls in the church complex are used for plenty of other functions, requiring less hands-on control. “The Audia system is great, because everything's dialed in so anyone can use it,” Whittle says. “All the mics feed through the Audia automixer, which autolevels everything and runs preset DSP for every channel.
“Audia really allowed us to add a lot more flexibility and control to their system at very little cost. We were able to not only solve the existing problems, but also we managed to solve a few more they hadn't even noticed.”
The only remaining challenge will be next year, when the second pipe organ that has been on order for two years finally arrives, and to change the acoustics of that flat wall behind the stage yet again. Whittle is optimistic: “The pipes will act as a diffuser and make the room a little more stable.” With the odds that have been conquered already, one tends to believe him.
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