May 17, 2011 11:24 AM, by Dan Daley
How BYU integrated a multi-facility system.
Starting nearly five years ago, the project’s loudspeaker design began to be modeled by acousticians Ben Seep and Ed Logsdon of D. L. Adams Associates based on the architectural renderings, using the EASE software program. Kenneth R. Fause, a principal at Auerbach Pollock Friedlander, handled subsequent follow-up with EASE modeling. Prager says the PA system design and components underwent numerous revisions over subsequent years. “One of the big lessons you take away from a project of this size and scale is that over the course of such a long time, products change and new versions become available,” he says.
For instance, while a Yamaha PA system had been chosen early on based on the use of Nexo components in other areas of the campus (there is a Geo S8 system in the cafeteria), components changed over time, with the under-balcony delay speakers changing from short D10 stacks to Danley Sound Labs, to in-ceiling JBLs, and eventually to Nexo S1230s. The introduction of the Nexo Nxamp 4x1 and 4x4 amplifiers integrated with loudspeaker processing changed the system design fundamentally. “We were able to deliver the MA DI digital signal from the mixing console to the Yamaha DSPs, utilizing EtherSound outputs, directly to the amplifiers without any digital-to-analog conversions,” says Prager. “Because we’re not running audio on the network, there’s minimum latency, and if the network were to fail, you’re not going to lose audio.” After the installation, Yamaha also upgraded the DME 64N 24-bit, 96kHz DSP processors that had been purchased prior to the upgrade becoming available. Prager estimates that as much as two-thirds of the components’ specifications were changed before the final system was installed.
Getting coverage to the balcony areas was crucial. “There are three levels of balcony fills: over-balcony, under-balcony, and under mezzanine,” Prager says. “There’s a natural combination of high-frequency and SPL loss over distance, so the design calls for [the fills] to pick up the sound from the delayed speakers right at the point where the top end rolls off when someone is seated in a certain position in order to maintain high intelligibility and evenness of sound. The balconies will cut the upper frequencies off faster than the mids.”
David Mann says that 107 Nexo S1230 speakers were used to distribute sound in the delay fill areas, each with its own amplifier channel and DSP processing, which is used to sum the three-channel L-C-R audio signals to mono. However, that is mix-matrixed with EQ and delay to favor the appropriate channel on either side of room (the left half of the room in the distributed system would hear more of what is coming from the left side of the hanging cluster). “Having the audio sources directly overhead can be distracting to the listener, and this helps keep the focus on the stage as well as keep the [stereo] image intact,” Mann says. The S1230s are mounted within ceiling soffits using a U-bracket and covered with acoustically transparent custom grilles. A series of 15 front-fill speakers use a combination of Nexo S1230 cabinets with 80-degree and 120-degree horizontal dispersion patterns, with 30-degree vertical dispersion patterns. These fill speakers under the stage lip enhance the audio for the front 10 rows, are also L-C-R mix-matrixed, and delayed to the main line arrays.
Mann says the fill part of the system at the rear of the hall needed to be highly controllable and directional to match the Nexo line array, which is able to be very precisely steered and targeted. “On the left and right line array hangs, the 18 boxes are grouped in threes. That lets us divide each array into six sections of three boxes each that we can shade with various types of EQ and other processing to do things like compensate for air loss in the longer throws,” he says. The quality of the signal chain extends all the way to the podium, where a Schoeps CMC 6 microphone with a high-rejection MK4 cardioid capsule is positioned. “The lectern is almost directly under the center cluster and gain-before-feedback would be a potentially big problem, so we had to use a microphone with very high extraneous noise rejection capability,” he says. At the center cluster, there is also an array of five Nexo Geo D10 speakers firing toward the stage for the choir during a performance. Nexo amplifiers located in four different rooms, each housing an average of 16 amps, drive all of the speakers. A fifth amp room is used to drive the 60 downfiring speakers that feed the 10 basketball courts directly adjacent to the theater.
In addition to the sound systems, Diversified Systems also built the building’s broadcast center, fitted with an Evertz broadcast routing switcher, HD-video 250x400 (576 two-frame), 192x192 channels of AES audio, and 16x16 MA DI streams. There are 20 camera positions located throughout the theater that feed two production control rooms, two audio sweetening rooms, a voice-over booth, as well as three offline editing suits, camera shading, media transfer, and a master control room. The new Events Center is the final touch that completes the BYU-Idaho campus, which will be joined by another in Honolulu in the near future.
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