The church's dual dilemmas stemmed from the spectral characteristics of the sanctuary's architectural acoustics. Any sound system that fully excited the room would produce high-frequency reverberation certain to impair voice intelligibility. At the same time, low-mid reverberation needed for depth and fullness in organ music and congregational singing would be seriously deficient. Further architectural changes to remedy the situation would have been prohibitively expensive, and likely detrimental to the visual aesthetics of the room, as well. Fortunately, consultant and audio system designer Bill Schuermann of Houston-based HFP Acoustical was able to craft a solution by first controlling dispersion of the direct sound with Meyer Sound self-powered curvilinear arrays, and then creating a controlled reverberant environment using LCS Audio's VRAS variable room acoustic system.
In designing his arrays, Schuermann faced a significant restriction. The church was insistent there be negligible impact on the visual effect of the soaring stained glass window behind the chancel. "The key to success was focusing as much energy into the seats as I could with the smallest possible cluster," he says. "We also needed excellent speech intelligibility and tight pattern control. That's what we achieved with the Meyer Sound arrays."
To provide uniform coverage for the long, 990-seat sanctuary, Schuermann specified two identical clusters, one in the front of the room, the other a rear delay array, each consisting of five M1D ultra-compact curvilinear array loudspeakers and an M1D-Sub ultra-compact subwoofer. Individual M1D cabinets cover the much shallower transept seating, and a row of eight MM-4 miniature wide-range speakers are tucked inside the chancel steps to provide fill for the first two rows.
Schuermann and HFP colleague Thaddeus Leopoulos used Meyer Sound's MAPP Online Pro acoustical prediction software to predict coverage for each cluster with pinpoint accuracy. The results amazed Dan Simeone, volunteer head of the church's AV committee. "Bill modeled the new system for me early on," he recalls, "and I thought it would be wonderful if they could do what they were showing me. Well, they did. The system does exactly what the drawings show."
Along with enhanced intelligibility, the new system greatly extended gain-before-feedback, says Simeone. "With the old system, you really had to push [the system level] up to get sound in the back, but then you'd run into trouble with the sound going everywhere. Now, we simply don't have that problem."
With the coverage problems solved, the HFP team turned to the knotty problem of room reverberation. With the tight pattern control of the M1D arrays, the sound was fine for speech and amplified music in the contemporary services. But it was far too dead and dry for organ music, choir, and congregational singing in the traditional services. What the church needed was a way to change the room acoustics at the touch of a button, which HFP achieved by specifying the VRAS system.
VRAS uses a combination of microphones and loudspeakers placed strategically throughout a room, in conjunction with a powerful digital audio engine, to emulate any number of spaces equal to or larger than the actual room. The effect is extremely natural because the room's own acoustics are part of the system. CUMC's VRAS engine is connected to 16 Countryman Isomax microphones and 44 small loudspeakers placed overhead and around the walls of the room.
After the Meyer Sound and VRAS systems were installed by Core Systems of Houston, the VRAS system was fine-tuned to both the room acoustics
