Jan 18, 2012 1:07 PM, By Carolyn Heinze
5 line array challenges
The Unintelligible Historical Building
Dating back to the 1870s—when it was known as St. Mary’s—St. Mary Cathedral is the seat of the Austin, Texas, diocese, encompassing 125 parish churches/communities and serving more than 450,000 parishioners. The facility’s design draws upon natural themes, featuring intricate vineries that intertwine with its murals, stately columns constructed to look like trees, and a star-dotted dome.
A costly loudspeaker system installed in 2004 was not delivering on speech intelligibility or the kind of natural sound that would match the church’s organic design, says Ken Dickensheets—principal consultant at the Austin-based acoustical consulting firm Dickensheets Design Associates—adding that the existing system had problems with reliability and service. Based on prior experience with both the room and the speakers, Dickensheets recommended replacing the system with Tannoy QFlex 24s arrays with the goal of fulfilling two main requirements: superior audio and a discreet aesthetic footprint.
“Empirically it was agreed by everyone involved in the project that the QFlex actually delivered higher speech intelligibility and a more natural sound than the more expensive arrays that they replaced,” Dickensheets says. Two QFlex 24s—mounted approximately eight feet from the floor—flank the chancel and face the front of the sanctuary head-on. Dickensheets admitted that this does place some of the mics directly in line with the loudspeakers, but he declares that there is no feedback. The project team also put the QFlex BeamEngine GUI to use to direct sound off of the rear wall while at the same time maintaining coverage for the main sanctuary and choir loft.
Tracy Frederick, technician and project manager at Austin Audio and Video—the firm that oversaw the actual install—noted that the most challenging aspect of this project was the installation of the brackets used to mount the speaker arrays on walls that date back to over a century. “They’re stucco but with natural limestone behind them, and they’re over 120 years old. But once the brackets were installed, the speakers went up easily,” he says.
A number of pre-existing devices were integrated with the QFlex system, such as an Ivie 884 auto mixer, Shure P-4800 digital signal processing, and a wireless microphone system by Audio-Technica. Several QSC CS series amplifiers drive the facility’s subwoofers in addition to the 70V loudspeakers that are installed in the narthex, cry room, and outdoor areas. Because there is no console, speech is mixed through the Iive unit; during musical performances, a remote control is connected to it, enabling users to transform it into a manual mixer. There are eight microphone inputs in all, four of which are wireless. Reinforcement for the choir is achieved through a separate system.
Carolyn Heinze is a freelance writer/editor.
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