May 17, 2011 11:24 AM, by Dan Daley
How BYU integrated a multi-facility system.
The college that prays together stays together.
At least, that simple aphorism is part of what was behind a new Event Center facility that’s the core of Brigham Young University Idaho’s (BYUI) new multi-purpose facility for its new campus in Rexburg, Idaho. Officially known as the BYU-Idaho, the three-year ground-up construction project offers a massive gymnasium with 10 3/4-sized basketball courts and a 15,000-seat auditorium, with separate and complex sound systems for each space.
The auditorium’s size was based on the maximum number of students and faculty that the entire campus can accommodate in order to bring them together for the Mormon school’s traditional Tuesday devotional services. These had been held in a smaller 4,300-seat building on campus and then broadcast on the school’s fiber-cabled AV distribution system to seven other campus venues. That was an effective use of AV technology, but still not the same thing as being together for an intensely spiritual institution. “It’s a very big project that was based on that premise, but that gives you an idea of how important that gathering is to the school,” says David Mann, BYU-Idaho Center’s mixer and audio engineer.
The school gets a lot of use out of the 434,000-square-foot center. In addition to basketball, the 97,000-square-foot gym is used for tennis, volleyball, indoor soccer, as well as educational presentations and the first dance. That side of the building, separated by a large foyer from the auditorium, has four portable racks on carts each fitted with an Alesis iMultimix 9R mixer with an integrated iPod dock, a Tascam CD-01U Pro CD player, and a mic input panel. These can be connected to any of four inputs that feed the gym’s PA system. This is comprised of a Yamaha DME64N digital mixing engine and divided into 10 zones of Electro-Voice SX300Pi loudspeakers, which are configurable and controlled via a Crestron TPMC-12LB touchscreen that interfaces with the DME 64N to feed Yamaha PC4801N power amplifiers. However, there are no acoustical barriers, only curtains to separate the courts visually. When the gym is used in a divided mode, zones will overlap, which requires that levels be kept relatively low. Mann says the gym’s sound system is more intended to address possible future needs rather than any specific current ones, but he says that it has performed well the few times it has been use since the facility opened in January.
The BYU-Idaho Center’s much larger (337,000 square feet) auditorium is a full stage-house theater—and its sound system is also far more complex—in response to the building’s interior architectural design. In a combined point-source and distributed design using Yamaha’s Nexo systems components, three main L-C-R clusters hang in front of the 105’x70’ stage. Left and right arrays house 18 GEO D10 speakers in each cluster, configured such that at the bottom of each array, a Nexo S1230 side-fill fires downward, a design to address the auditorium’s enormous fan-shaped design. The center array consists of 14 Geo D10 cabinets, with four S1210s as down-fills paired on each side of the cluster. There are four Nexo GEOSUB subwoofers at the top of each cluster. “The sub frequency cabinets are positioned at the top of each cluster, and the D10 boxes are precisely aimed downward to suit maximum evenness of coverage in the vertical plane,” says Andy Prager, senior project engineer at Diversified Systems, the systems integrator on the project. “There was concern about placing the subs at such a high elevation in this large volume open space, [since] there’s a lot of air to push. So it was decided to add subs to the design, where under certain circumstances—such as amplified music performances—dual-stacked Geo Subs could be rolled out on each side of the stage, using separate mix outputs from the DiGiCo SD7 console. Since both flown and stage subs have discrete mix output channels from the console, the mix engineer can use faders as a gas pedal to suit sub-frequency gain requirements.”
While music is one of the applications for the auditorium, as well as theater performances and large group meetings, the overriding mandate for the systems’ performance was that its speech quality be highly intelligible since its primary mission was the weekly devotional services. “The challenge was to get even and highly intelligible coverage throughout the entire auditorium, despite there being some architectural challenges,” says Prager, with a goal set of ±2dB variation within the space, there is no more than ±3dB variation in level with frequency response up to 12Khz. These included the raked angle calipers on the sides and two jutting balconies necessary to accommodate 15,000 seats into the space.
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.