When the Biamp team arrived at Georgia Southern University’s football stadium for what should have been a routine sound system commissioning, they faced what would typically be considered a disastrous situation. The newly installed LVH-900 loudspeaker arrays were already mounted high above the scoreboard, but they appeared to lack sufficient downward tilt to properly cover the seating areas. With installation crews and equipment long gone — and the season opener just two weeks away — this seemed like an impossible situation to remedy.
“The loudspeaker arrays were installed, aimed, wired to the amps and ready for testing. From a visual inspection, it appeared that the arrays weren’t aimed down quite enough,” says Charlie Hughes, principal engineer for electroacoustics at Biamp. “We investigated the possibility of making minor adjustments, but that was not possible.”
The commissioning had to be completed by the end of that week, as the integrators were scheduled at another location the following week. For conventional loudspeaker systems, this timeline, combined with the mounting issues, would have necessitated expensive reinstallation work that simply wasn’t feasible.
Electronic adjustments save the day
What saved the project was the LVH-900’s electronic beam-steering capability. This innovative technology allowed the Biamp team to address multiple challenges without physically touching the loudspeakers.
The first step was updating the simulation model to reflect reality. “While walking the stadium and listening to the right array, our beam-forming guru, Xian Yu, noticed that some things in the stadium didn’t seem to match the Focus 3 model she was using,” Hughes says. “We measured a few aspects of the stadium relative to field level and confirmed that the Focus 3 model provided to us had significant errors. The stands in the model were about 20 feet higher than in reality.”
This error meant that much of the sound energy was being directed 20 feet over the seating area and hitting the press box, creating disruptive reflections. For traditional fixed-directivity loudspeakers, this would have required physical repositioning with a large crane — an expensive and time-consuming process.
Instead, team members leveraged the LVH-900’s electronic beam-steering capabilities. They redrew the stadium’s correct dimensions, specified exactly which areas should receive sound and which should be avoided, and used specialized software to create updated beam-forming FIR filters to optimize coverage.
“We knew we could reconfigure the vertical coverage of the LVH arrays by generating a different set of FIR filters,” Hughes explains. “This was only possible because the installation was taking advantage of the custom, asymmetrical beam-forming capability of LVH, which is quite different than the standard configurations.”
After loading the new filters into the amplifiers, the press box reflections disappeared completely.
Facing new challenges
Just when it seemed the problem was solved, the team discovered another obstacle: a field house with brick and glass walls behind the opposite end zone was creating additional reflections and echoes that compromised intelligibility in some seating areas.
“After Xian generated a new set of FIR filters, the sound was much improved. But we now noticed a reflection from the field house,” Hughes recalls. “This was distracting in some seating areas. In others, it adversely affected intelligibility.”
Once again, the LVH-900’s electronic beam-steering capabilities provided the solution. The team added the field house to their model and designated additional avoidance zones where reflective surfaces were located. This allowed them to direct sound away from these problematic areas without physical adjustments to the speaker system.
“The FIRmaker® module in Focus 3 has a nice feature that allows designers to specify certain areas as avoidance zones,” says Hughes. “Xian worked some magic to properly configure a few new areas in the model to reduce the energy being directed at the field house.”
After multiple simulations to find the optimal balance between minimizing reflections and maintaining coverage, they implemented a solution that reduced field house reflections by about 6 dB while actually increasing sound pressure levels by 2 dB in some seating areas.
A third challenge — very late echoes from a practice field roof approximately 100 yards behind the field house — was also mitigated by these same electronic adjustments.
Impressive, without physical intervention
The final system required minimal equalization adjustments. “Using our Focus 3 simulations, I was able to determine most of the EQ that I thought would be needed prior to arriving on site,” Hughes notes. “It turns out that it worked remarkably well.”
Most importantly, the loudspeakers never had to be physically repositioned during the entire process. The beam-steering technology provided a flexible solution that adapted to the stadium’s actual dimensions and acoustic challenges.
“The coverage in the stadium was excellent. Sound quality, tonality and SPL were very consistent throughout the seating areas,” Hughes says. “We were all very happy with the results — the Biamp team, the integrator’s staff, the university’s athletic staff, everyone was thrilled.”
The project demonstrated the powerful adaptability of electronic beam-steering in modern audio installations. As Hughes points out, “It really showed the capability of LVH being able to adapt to the needs of the situation. The flexibility of modifying the vertical coverage pattern electronically to overcome unforeseen challenges probably saved tens of thousands of dollars, and weeks of time.”
The Georgia Southern installation was particularly well-suited for an asymmetric LVH system due to the extreme difference in distances between the closest and farthest seating areas — from about 130 feet to almost 600 feet away from the loudspeaker arrays.
“The DSP-controlled beam-forming capability of LVH allows for custom tailoring of the vertical coverage pattern,” explains Hughes. “We can direct more energy to the upper part of the pattern, that covers the farthest seating, and less energy to the bottom part, covering the closest seating.”
When Georgia Southern University played its first home game of the season two weeks later, fans experienced crystal-clear sound throughout the stadium — with no one the wiser about the behind-the-scenes audio wizardry that had saved the day.
FIRmaker® is a registered trademark of AFMG Technologies GmbH
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Biamp® is a leading provider of innovative, networked media systems that power the world’s most sophisticated audiovisual installations. Recognized worldwide for delivering high-quality products and backing each one with a commitment to exceptional customer service, Biamp’s mission is connecting people through extraordinary audiovisual experiences.
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