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The Wire

Sierra Linda High School Gets an “A” with New L-Acoustics A Series System

Clearwing Systems Integration installs compact constant curvature arrays at Tolleson Union High School District’s brand-new Performing Arts Center

When students are once again able to return to Sierra Linda High School on Phoenix’s west side, they’ll get to step inside of their school’s nearly 30,000-square-foot new Performing Arts Center, which will now serve as the home stage for all of SLHS’ visual and performing arts programs, from band and chorus to dance and drama. To ensure that the audio facilities are every bit as state-of-the-art as the new educational and entertainment space, Clearwing Systems Integration’s team specified and installed its very first L-Acoustics A Series loudspeaker system in the 584-seat venue.

Sierra Linda High School is one of two new auditoriums on which Clearwing has collaborated with Tempe-based architect ADM Group for the growing Tolleson Union High School District, the other being for West Point High School, which is still under construction and will also feature an A Series loudspeaker design.

With Clearwing Systems Programmer Aaron Frisbie and Designer Ryan Peavey partnering on the Soundvision model, the final system design for the Sierra Linda High School Performing Arts Center features left and right arrays, each comprised of two L-Acoustics KS21 subwoofers, one A15 Focus and two A15 Wide enclosures flown from a single bumper. To address the front-center seating area, seven compact coaxial 5XT speakers were tucked into openings across the face of the stage. Four LA4X amplified controllers housed in a full-sized Middle Atlantic equipment rack near the front of house mix position power and process the entire system.

According to Clearwing Systems Integration Design Engineer Jill Maurer, the architect wanted to provide blanketed coverage to support the needs of Sierra Linda’s space, but not encroach on the proscenium opening or the look of the frame. “One of the initial design challenges was to only provide side arrays because ADM Group did not want a center hang to compromise the sightlines,” she says. “With the recent availability of the powerful yet compact L-Acoustics A Series, we were able to position the arrays high and wide enough to keep the speakers out of the proscenium and away from the throw of the stage lights from the catwalk.”

“Normally, a venue of this size would call for a traditional line array; a constant curvature design would not be capable of providing the consistent SPL coverage we require,” says Frisbie. “But thanks to the adjustable L-Fins on the new A Series, we were able to steer the high frequencies away from the walls using the 90° asymmetrical setting to reduce reflections, plus focus the acoustic energy of the top enclosure to the back of the room using the 70° symmetrical setting. The A15 adjustable horizontal dispersion made this configuration possible and allowed us to achieve even and consistent coverage throughout the venue.”

Another one of the venue’s potential challenges pertained to the deployment of subs. “Being limited on space, flying the subs with the arrays was our only option,” describes Nick Dressler, General Manager – Clearwing Systems Integration, West. “Typically, when flying subs, we have to add more enclosures in order to match the SPL of the main PA, but in this case, the A15 is already capable of reaching down to 41Hz. Combined with the KS21 sub, we are capable of a low frequency extension down to 29Hz. The KS21 is also capable of a max SPL of 138dB, which puts it in league with most dual 18-inch subs on the market while still maintaining a slim, flyable form factor.”

Official system commissioning and training took place in late February, just prior to the school’s early-March spring break, during which the district announced that students would need to shelter-in-place at home for the pandemic, so the system will have to wait until fall to host official events. But that hasn’t stopped the school and Clearwing, which integrated all production elements—audio, video, lighting, stage drapery and motorized rigging—from deeming the project a complete success.

“L-Acoustics really did a great job with the creation of the new A Series and KS21,” Frisbie adds. “Their quality, ease of use, light weight and budget-friendly price point put them into a category all their own while still maintaining the power, clarity and sonic character that the manufacturer is well regarded for. Sierra Linda High School’s 5XT coaxials pair perfectly with the A15 arrays creating a seamless transition between the main arrays and frontfills. A Series has the same adjustable Panflex technology as K2, which allowed us to create a design for the client that also delivers the low frequency extension and control common to larger L-Acoustics line array systems. The combination of A15, KS21 and 5XT allows for an optimal listening experience for every seat in the house, and everyone is really happy with how well the project turned out.”

For details on Sierra Linda High School and its facilities, visit Clearwing Systems Integration can also be found online at