House Of Worship, News

With the Right Tools…

Sometimes, unique building design and a client’s aesthetic concerns conspire to force integrators to think outside the box. AV systems are never one size fits all, but every integrator has his or her tried and true methods and go-to solutions for typical installations. So, when a project comes along where the usual methods don’t suffice, it can be a major challenge. Fortunately, technology is constantly evolving, and the integrator’s toolbox is constantly expanding. This is why it is absolutely vital for integrators to keep up with the latest technological advancements and consider paradigm-shifting new products.

Escondido CA-based integrator Sound Image (sound-image.com) was recently involved in just such a project where the usual methods proved ineffective or impractical. San Rafael Catholic Church (sanrafaelparish.org), located in San Diego CA, contracted Sound Image to resolve significant speech intelligibility problems caused by an outdated sound system. These challenges were exacerbated by a recent remodel of the church’s main sanctuary, which made the already reverberant space even more so. Further complicating matters was the unique shape of the sanctuary, an octagonal room with seating in the round, and a peaked ceiling with a stained glass window at its apex. We talked to Mike Fay, General Manager of Sound Image’s contracting division, and Deacon Ward Thompson, who acted as the liaison between Sound Image and San Rafael, about how these issues were overcome. Other Sound Image personnel on the project included Project Engineer Ryan Ash and Project Manager Bob Delson.

According to Fay, the San Rafael project was brought to his attention by a longtime friend and business associate, Bennett Lord, Principal of Lord Architecture, who happened to be a parishioner at San Rafael. The church underwent a fairly extensive remodeling effort in 2013, which involved the removal of all of the main sanctuary’s carpeting, as well as installation of a stone wall behind the presider’s chair. When it was all said and done, the only absorptive surface left in the sanctuary was the padded seats on the pews. As Thompson explained, exposing so many hard, reflective surfaces made the church think twice about “what we used to think was fair acoustics and a fair sound system.”

Once the remodeling was complete, the church received a number of complaints. “We had complaints from parishioners, especially elderly parishioners, that there was what they would describe as an echo, a reverberation, something that arose out of a lack of synchronization,” recalled Thompson. “And we noticed that there were some spots in the church, in the pew area especially, where the sound was a little bit better than in other places. So, there were some inconsistencies.”

The church hadn’t upgraded its sound system in around 10 years, so its leadership figured that a change was in order. The old PA system consisted of eight loudspeakers arranged around the stained glass window, with a speaker installed on each of the eight facets of the octagonal pitched roof soffit. “The loudspeakers they had in there before looked fine, but they weren’t the appropriate box in terms of painting the seats with sound and not overly exciting the rest of the room,” said Fay. “They were very low-Q boxes, like six-inch two-way. When they took all of the carpet out of the room, the room went from a drier perspective to a wetter perspective in terms of reverb.”

Fay had some ideas for a new system in mind, but many of them wouldn’t jive with San Rafael’s aesthetic preferences. “It was a tricky room because it’s fairly lively, and aesthetically, they wouldn’t let us do what might be considered more traditional loudspeaker placement,” Fay elaborated. “There’s a lot of visual emphasis on the wall behind the ambo, which is where the pipe organ is and where they did a lot of the remodeling a few years ago, so that whole wall was off limits. Anything hanging from the ceiling was off limits. The only thing that made sense was to hang speakers from the octagon soffit up top, where they had the old speakers. But, because there are six seating sections, we would have had to put six rather large point-source-type boxes up there, and the church didn’t want to see six big boxes hanging.”

The solutions that weren’t disqualified by aesthetic concerns were disqualified by the limitations imposed by the unique shape of the room. “We talked about putting steered line array columns on the left and right side of the new organ wall,” Fay offered. “The problem with that was, shooting horizontally from one side of the room to the opposite side, the side walls, because it’s an octagon, are collapsing. And electronically steered column arrays have wide horizontal dispersion so, as the wall is collapsing on the horizontal plain, the throw for the right half of the center line is considerably farther than the left half of the center line. Plus, we would have had to fire over the choir on one side of the room but not on the other side of the room, so we would have had asymmetrical steering. That’s not ideal.”

Fay was admittedly stumped at first. “I’ve been doing this a long time, and I consider myself a pretty creative thinker, but I walked out of the first meeting saying, ‘I’m gonna have to sleep on this one.’ I just couldn’t figure out how to do the job the way I might have approached it typically,” he recalled. However, a chance encounter from a few months before had provided Fay with a workable solution to this riddle. “I remembered a meeting with some of the Tectonic guys at InfoComm,” he explained. “I just wandered into their booth because I saw their speakers hanging up there and thought they were unlike anything I’d seen before. We talked, and none of the stuff they were saying made a whole lot of sense, because I come from more of a Don Davis traditional sound engineering perspective. But the day after that first meeting at San Rafael, after sleeping on it, the idea popped into my head that this Tectonic product I had talked to these guys about might be worth considering; I couldn’t think of any other approach that made sense.”

Fay decided to design a new sound reinforcement system built around three Tectonic PL-12 loudspeaker panels. According to Fay, “What Tectonics is trying to bring to the table is an argument that says ‘Our speakers will provide better intelligibility in a difficult acoustic space because they don’t propagate sound the same way a more traditional pistonic loudspeaker does.’ The DML [Distributed Mode Loudspeaker] panel seems to behave like the sound board of an acoustic piano. The piano makes sound, but the strings alone aren’t generating much energy: It’s the sound board and the lid that provide the amplification. Because the PL-12 panels don’t push sound hard into the room the way a pistonic speaker would, the sound is radiating throughout the room, and from fewer devices.”

The chance to use fewer boxes, while improving coverage and intelligibility, presented exactly the solution Fay was looking for. “Instead of having several sources degrading intelligibility from a timing reference, you can use fewer devices,” he explained. “As anyone who designs systems knows, the more boxes, the more things that you have to worry about in terms of time and coverage. At the end of the day, my goal was to not overexcite the room, because it has about a 1.8-second mid-band T60, and that’s certainly not helpful when it comes to speech intelligibility.”

Fay reached out to Tectonic about setting up a demo in the church. “That’s a pretty important piece of the story, because I didn’t know what I was getting myself into,” said Fay. “I’d never heard the speakers before. All I did was talk to the guys about their new technology, which I didn’t understand or relate to at all. So, I’m on the hook here for the design and I’ve got one of my best customers, who’s an architect, and he’s given me his own personal church to fix. There’s a little bit of stress there.”

As it turned out, the timing couldn’t have been better. “Tectonic was doing a demonstration road show throughout the southwestern US at the time, and they were going to be in San Diego,” recalled Thompson. “We had a demonstration and the speakers sounded great. So, we decided to go ahead and do it.”

San Rafael’s sanctuary features seating in the round, with 315° of pews facing toward the altar, which is in the center of the octagonal room more or less directly beneath the stained glass window at the apex of the ceiling. The remainder of the octagon that does not include seating for the parishioners is devoted to the altar area, which includes the presider’s seat, the ambo and the remodeled rear organ wall. The three Tectonic panels are arranged around the stained glass window in such a way as to cover the entire seating area, hung from glulam beams that support the pitched ceiling.

“The speakers are mounted like projectors,” explained Fay. “We had to do a little bit of custom rigging work. For each panel, there’s a PDR CPM100 cathedral mount screwed into the bottom of the glulam beam. We then dropped a foot-and-a-half PDR threaded pipe down to another cathedral mount. We couldn’t buy anything that would give us the down tilt angle we needed, but using a second cathedral mount did the trick. The back of the speaker then goes to a custom adaptor plate that we designed and made locally to adapt the cathedral mount to the VESA mount footprint of the Tectonic panel.” Each of the panels is further secured by aircraft cable. According to Fay, “In California, you have seismic issues to deal with. The rigid mount of the threaded pipe takes care of most of that, but the cables give us a little extra for the seismic aspect, and also act as a safety if something were to go wrong with the main attachments.”

Fay had some concerns when it came to the speakers’ dispersion patterns and ensuring even coverage to the seating area. “The vertical dispersion of the DML section of the panels is about 140° to 160°, but the HF ribbon’s only 15,” explained Fay. “Because all three speakers are tipped down at a fairly severe angle, we needed to confirm the down angle with only the ribbon on. We had pink noise going through the HF section, and our PM up in the lift tipping the panel, while I walked the pattern, front to back, so we could be sure we had the optimum high-frequency coverage. The final panel height is about 32 or 33 feet straight up from the ground. We were high enough up that the 15° vertical coverage coming out of the ribbon just happened to fit the depth of the seating perfectly. If we were a little bit closer to the seats, it would have been too narrow.”

Although the loudspeaker panels are visible near the ceiling, the church had grown accustomed to having sound reinforcement equipment in this area because that was where the old speakers were located. Also, a custom-color powder coating on the panels lessens the visual impact. “These are not invisible speakers, but they have a very clean profile to them,” said Fay. “They also happen to have incredibly wide horizontal dispersion, and the layout of the glulam beams allowed us to have excellent symmetry in terms of how things got placed, so we could mount one speaker every 90° and cover 315° of seating with three sleek devices instead of six bulky ones.”

Because Fay was working with unfamiliar technology, the commissioning process involved more trial and error than usual. “You can’t really model these DML panels in EASE or anything like that,” he explained. “So we have three of these devices up high, tipped down significantly. The bottom half of the DML section vertical dispersion piles on top of the altar because they’re more or less directly above. We have two panels that are wired in parallel, so everything we do to one happens to the other one. The speaker in the middle was set up so we could play around with it. We flipped the polarity to see if that made a difference at the altar, but it didn’t make enough difference to matter.”

After further experimentation with the central panel, Fay and his team arrived at a solution. “By delaying the center speaker of the three, it seemed to help clean up the spill onto the altar a little bit. We’ve got crossover timing delay between the ribbon and the DML panel, and then we have a little bit of macro delay on the center panel to push it a little bit out of time relative to the other two. What you might hear with more traditional speakers, when there is significant coverage overlap, is all kinds of comb filtering and other nasty stuff. With this system, there was no noticeable comb filtering.”

Although this system avoided some of the common pitfalls of more typical sound systems, it did require some fine tuning. “There was a little thickening of the low/mid section in the seating area between any two panels because there was quite a bit of horizontal coverage overlap between them,” said Fay. “The sound got a little thick in the 200Hz to 400Hz range. It just took a little bit of EQ to mellow it out.”

The main sanctuary shares an open wall with a side chapel area that is used for overflow seating. According to Thompson, “Mike got on his computer and determined the speed of the sound wave from the nearest speaker pointing in the direction of the chapel opening, then set the timing such that the people sitting in the chapel would not pick up any delay at all from the speaker in the church. It’s perfectly in sync.” During the EQ process, Fay used Rational Acoustics Smaart 7 software, a Lectrosonics TM400 wireless test and measurement system, an iSEMcon reference mic and a Sound Devices USBPre.

Despite Sound Image’s lack of familiarity with the centerpiece of its system design, the San Rafael installation was not a very long process. “On the jobsite, we were in and out between Monday and Friday,” said Fay. “There’s a few reasons why. We didn’t need to supply a new rack. We just gutted the existing rack and rewired everything. The wire path that went up to the old speakers was reused because there wasn’t a path to put new wire in without ripping open the ceiling. Fortunately, they had 12-gauge going up there and that was good enough for what we needed.”

In addition to the DML panels, the new system includes a QSC CX354 4-channel power amp (Fay described himself as “a lifelong QSC guy”) and a Symetrix Radius 12×8 DSP, which handles all the system’s inputs and outputs and is supplemented by an XLN-12 Expansion Module. “Every input has a high pass filter, parametric EQ and a compressor, while every output has a high-pass filter, parametric EQ, before-and-after crossover, a compressor and limiters. A gain-sharing auto mixer does a great job keeping things under control, especially when they are using a lot of untended, open mics. It’s not unusual to have 10 or more open area mics servicing the choir,” explained Fay.

“The PL-12 panels are biamped,” he added. “We’re using four amp channels because we have two opposing panels that are running in parallel on two of the amp channels and a single panel that’s running biamped by itself on the other two channels. One of the things that’s making this all work is that I’m not afraid to use DSP to fine tune every input and output as much as necessary.” A Furman M-8S 3-stage power sequencer controls power to the amp, while an F1000-UPS powers the DSP. “We’ve found that, long-term, the DSPs that stay on 24/7 are most stable when hooked up to a UPS,” said Fay.

The system is almost entirely hands off, which was San Rafael’s preference, because the church does not have any dedicated AV staff. “We have a rack of equipment in the sacristy,” said Thompson. “Basically there’s a toggle switch on the outside and when we want to have a liturgy, we flip the switch. We have a key to the cabinet and there are certain adjustments that we feel comfortable in making, like volume for the speakers in the cry room, chapel and narthex, but basically we just don’t touch it. We just turn it on and off.”

According to Thompson, the church couldn’t be more pleased with the new system. “As far as the spoken word is concerned, it completely resolved the issue. Sound Image just did a great job. I’d highly recommend the company to anyone.” San Rafael was so impressed, church leadership is currently working with Sound Image to upgrade its choir sound system from analog to digital.

For his part, Fay was glad to have seen his loudspeaker gamble pay off. “I think, at the end of the day, this is speaker technology that a lot of people, and I’m including myself, struggle to express how and why and if it works,” he said. “I think it’s well suited for certain applications, just like everything else that’s out there. It’s a tool in the toolbox. Sometimes you run into a situation where this is the best tool for the job.”

Previous ArticleNext Article

Send this to friend