Installations

A Sound Of Thunder In Oklahoma City

The main loudspeaker arrays consist of two side-by-side columns of adaptive array modules hanging above the sides of the scoreboard. The north and south arrays are six modules high, whereas the east and west arrays are four modules high. Subwoofer arrays hang above the corners of the scoreboard. Four three-way loudspeakers are mounted to the bottom of the scoreboard. These provide down-fill coverage to the closest courtside seats and serve as monitor loudspeakers on the court during timeouts and halftime.

Equipment List [PDF]

A complete sound system renovation was completed at the Chesapeake Energy Arena (CEA), home of the Oklahoma City Thunder NBA basketball team, in time for its first preseason game on October 16. The 580,000-square-foot building interior is 130 feet high from arena floor to roof. Seating is more than 17,000. CEA is managed by entertainment and convention venue management company SMG. The facility also served as home to the Oklahoma City Blazers, Oklahoma City Yard Dawgz and the New Orleans Hornets in past seasons. In addition to sports action, the arena serves up the excitement of live concerts and other world-class events for more than one million guests.

Although CEA is managed by SMG, the venue is owned by the City of Oklahoma City (OKC) and was the premier project of its visionary capital improvement program (MAPS) to finance new and upgraded sports, entertainment and convention facilities with a modest penny sales tax.

Since opening in 2002, a number of improvements have been made to the facility, including new restaurants, speakers, video boards and security features. In 2008, OKC voters overwhelmingly approved another temporary one-cent sales tax to fund several major upgrades. That project featured new terrace suites and lounges, bunker suites, as well as renovated locker rooms, a new grand entrance with a multistory atrium, new restaurants, club concession areas, team offices and a family fun zone.

Ford AV, Oklahoma City OK, was the installing contractor. We talked to Project Manager Kevin Compo and Project Engineer Brent Kuchero. Marsh/PMK International, LLC, headquartered in Richardson TX, was the design consultant. We spoke with President David Marsh, project manager for the overall project, and Jerrold Stevens, Associate Principal and Director of AV systems, based at Marsh/PMK’s office in Georgetown TX.

Overview

The commissioning team for the new sound system includes Marsh/PMK’s David Marsh (left, rear), Ford AV’s Brent Kuchero (right, rear) and Marsh/PMK’s Jerrold Stevens. The new digital mixing console in its road case can be seen in the background (being operated by Kuchero). This was specified so the sound could be mixed from out in the arena rather than in an enclosed booth.
The commissioning team for the new sound system includes Marsh/PMK’s David Marsh (left, rear), Ford AV’s Brent Kuchero (right, rear) and Marsh/PMK’s Jerrold Stevens. The new digital mixing console in its road case can be seen in the background (being operated by Kuchero). This was specified so the sound could be mixed from out in the arena rather than in an enclosed booth.

Our report includes information gleaned from the 34-page CEA Sound Study and interviews with consultants Marsh and Stevens. Acoustic and electroacoustic measurements related to the installation are best expressed in accompanying graphics.

“The entire loudspeaker system was replaced, except for existing distributed speakers that cover club-level seating just in front of the suites,” explained Marsh. “The real story, though, is that this is the first NBA arena to install EAW’s Anya system, a digitally adaptive array technology. Both the Thunder and OKC were excited by our presentation of the system’s capabilities. We are happy that they selected this advanced technology solution over the prevailing line array approach or a conventional point-source option, which was the arena’s previous existing system type.”

Concept model of point-source arrays arranged around the scoreboard with a subwoofer array above the scoreboard.
Concept model of point-source arrays arranged around the scoreboard with a subwoofer array above the scoreboard.

Marsh/PMK presented three different loudspeaker system options, which we’ll highlight here. “We designed three system types and described the pros and cons of each in terms of audio performance, operational considerations, structural and electrical ramifications, project scheduling factors and estimated costs. The base bid was a line array system, but there were multiple alternates, including motorized rigging and the Anya system with and without subwoofers.” Marsh added that the design included a new digital console and an alternate mixing location, moving the console out of a booth above the “nosebleed seats” to an area at the front of the upper level, where the operator could hear what the crowd hears.

Modeled SPL map and statistical SPL distribution for the point-source system concept. Coverage uniformity is ±2 dB averaged over the frequency range of 1 to 4kHz.
Modeled SPL map and statistical SPL distribution for the point-source system concept. Coverage uniformity is ±2 dB averaged over the frequency range of 1 to 4kHz.

Extensive acoustical treatment was specified to mitigate echoes and reduce reverberation in order to make the new sound system as intelligible as possible. Sound-absorbing treatment includes “acoustical signage” (perforated vinyl signs over fiberglass) on the wall above the last row of upper-level seats, vertically mounted “acoustical banners” above this signage and about 65,000 square feet of banners mounted horizontally to the underside of the roof deck. Additionally, “acoustical signage” is being installed on the front faces of Terrace Suites at each end of the arena. A greatly compressed project schedule made the simultaneous installations of sound system and acoustical renovations impossible prior to the start of the NBA season. Consequently, acoustical work is ongoing when the arena is available between home games.

Modeled speech intelligibility map and statistical STI distribution for the point-source system concept without the recommended acoustical treatment. The mean value of STI is 0.51 and the highest value is 0.58.
Modeled speech intelligibility map and statistical STI distribution for the point-source system concept without the recommended acoustical treatment. The mean value of STI is 0.51 and the highest value is 0.58.

“We started this project in December 2014,” said Marsh. “At that time, the arena was 12 years old. The team was not happy with the sound quality. Speech intelligibility and music clarity were lacking. They felt the system didn’t have enough ‘punch.’ There were some reliability issues with speakers not working and sound cutting in and out. Facility management also told us that concert promoters had complained about excessive reverberation in the arena. In summary, the team and the city deemed sound quality to be substandard for a modern NBA arena.”

Modeled speech intelligibility map and statistical STI distribution for the point-source system concept with the recommended acoustical treatment. The mean value of STI is 0.56 and the highest value is 0.64.
Modeled speech intelligibility map and statistical STI distribution for the point-source system concept with the recommended acoustical treatment. The mean value of STI is 0.56 and the highest value is 0.64.

Design Option #1

In March 2015, Marsh/PMK submitted a Chesapeake Energy Arena Sound Study Report, which thoroughly examined the acoustics and the performance of the existing sound system. The report documented conditions affecting sound quality and presented recommendations that would correct deficiencies. Three different loudspeaker design options were studied. Acoustic and sound system analyses were performed, variously, in both EASE and Modeler acoustical modeling programs.

“We wanted to make ‘apples-to-apples’ comparisons between point-source, line array and adaptive array solutions,” explained Marsh. “Because EAW is currently the sole manufacturer of digitally adaptive arrays, we modeled all three system types based on EAW products. This enabled us to fairly compare the performance and cost of the three design concepts without the possible skewing effect of pricing differences among multiple manufacturers.”

“The first option was a traditional system of point-source loudspeaker clusters arranged around the center scoreboard with supplemental distributed speakers to cover the upper-level seating. This approach is sometimes referred to as an exploded cluster system,” said Marsh.

According to the CEA Sound Study, the first option design was based on EAW QX Series boxes. The point-source loudspeaker arrays would be arranged around the scoreboard with a single subwoofer array hanging above the scoreboard. Prime advantages of this approach would be low cost, little structural impact, excellent coverage uniformity and less noticeable interference between sources than a line array system. A proposed improved satellite system to cover the upper-level seating would minimize sound hitting the “drum wall” above and behind the top row of seats. Satellite speakers would be aimed at a steep enough angle to avoid causing disturbing echoes that were present with the existing system.

Disadvantages of the point-source approach included extensive re-cabling and rigging for the upper-level satellite loudspeakers and extensive rewiring of signal processing and amplification. Structural implications of a 2500-pound subwoofer above the scoreboard was another possible downside compared with the Anya system, which would function well without subwoofers.

Second Option

The second option was a line array system, which the team was predisposed to because they were impressed with several of these that they had heard in other arenas. Furthermore, virtually all concert touring systems are line arrays, making this a “tech rider”-friendly choice for various types of shows in the arena that might consider using the house system. Marsh/PMK’s proposed design was based the EAW KF740 line array modules, which were installed in the Barclays Center in Brooklyn NY.

Advantages cited for the line array system included 7dB higher output than the point-source approach. The proposed implementation retained the upper-level satellite system described earlier, with its inherent echo-mitigating benefits. The main disadvantage cited was cost, which was estimated to be about twice that of a point-source system. The cost would rise further if motorized hoists were included. Other disadvantages were the same as those listed for the first option.

Third & Final Option

The EAW Anya adaptive system was the third option and the client’s ultimate choice for the arena. The advantages of this system are best explained in an interview. In discussing the attributes of the system, consultant Stevens was knowledgeable because he was the Director of Support and Education at EAW during Anya’s development. As for the colorful product name, Anya was named after a lady Russian spy in a James Bond movie.

Each transducer within an Anya module receives its own discrete processing and amplification. Power was relocated from the catwalk AV rack room to the scoreboard to accommodate the self-powered Anya boxes. There are 22 transducers, 22 channels of dedicated Powersoft Audio amplification and 22 channels of DSP all built into the box. Internal software adapts total system performance to produce an asymmetrical, yet coherent, wavefront with full frequency response across a coverage area defined by the user.

An Anya module is shaped to provide horn loading of mid- and high-frequency drivers for increased efficiency and horizontal dispersion control. As such, it blends beneficial aspects of both point-source and line array systems. However, its unique technology is characterized as adaptive because advanced signal processing applied to the sophisticated module design creates a wavefront that matches the seating area to be covered.

More Like A Point-Source Speaker

“The Anya system sounds more like a point-source speaker than a line array due to its incredibly clean impulse response,” said Stevens. “Being far more advanced than a vertically steerable array, it creates a single wavefront that matches the area you’re trying to cover. For instance, you have raked seating areas to cover in the lower and upper bowl that are separated by a horizontal band of suites. You want to avoid the sound-reflecting vertical surfaces in this area. Anya actually creates a custom wavefront to match these requirements in a single beam.”

“The system is easy to deploy because it hangs straight. There are no box-to-box angle adjustments. You literally just stack them up and fly them to the elevation you want. You define the seating area in EAW’s Resolution software, which then generates the processing and the required shape of the wavefront to cover that area.”

A factor in selection of this system for the arena was the convenience of changing the coverage pattern at the push of a button. “Suppose the arena has an event where they don’t need the upper seating bowl. They can recall the appropriate preset and the processing will change the output wavefront of the arrays to cover only the lower bowl and the floor,” Stevens explained. “This is in contrast to a line array system where you have to bring the arrays down, change the angles between all the boxes and send the arrays back up again. With [this approach], you just go to the computer and say, ‘Go with this pattern,’ and in seconds the pattern changes to suit your needs.”

Other advantages ascribed to the adaptive array system included 3dB higher output than the line array system (10dB above the point-source option), greatly reduced coverage overlap compared with line arrays, less rigging, smooth coverage of the upper level without distributed speakers, the possibility of excluding subwoofers, minimal cabling/rewiring and the shortest installation time.

Two disadvantages cited were higher cost than line arrays and greater structural loads. However, estimated cost differences between the adaptive and line array systems were largely offset by elimination of the upper-level distributed system, less infrastructure, greatly reduced labor and possible exclusion of subwoofers. The overwhelming advantages ultimately persuaded the client to select the Anya alternate. Alternates were also accepted for installation of the subwoofer system and motorized hoists.

Now we come to the actual install, as explained by Ford AV’s Compo and and Kucharo. The Anya arrays were hung around and above the scoreboard in the middle of the arena for coverage of the far ends to the close-in areas of the seating bowl.

Four Vertical Columns

According to Kucharo, there are four straight hanging vertical columns, each of which is positioned in the center of each side of the scoreboard. Specifically, there’s a pair of six-high, two-wide stacks shooting at the far ends of the arena. Then there’s a pair of four-high, two-wide stacks firing at the close-in sections of the bowl.

One of four subwoofer arrays. Each of these has six vertically stacked cardioid subwoofer enclosures.
One of four subwoofer arrays. Each of these has six vertically stacked cardioid subwoofer enclosures.

Whereas the Anya columns are hung above the four sides of the scoreboard, four subwoofer arrays hang above the four corners. Each subwoofer array has six Fulcrum Acoustic CS121 units stacked vertically. The sub enclosures employ passive cardioid technology developed by audio engineer David Gunness, Co-Founder of Fulcrum Acoustics. Marsh/PMK selected these enclosures to minimize sound energy directed toward the rear of the arrays. Stacking the subs provides vertical pattern control, thereby improving low-frequency coverage uniformity in the seating areas while eliminating the typical “hot spot” on the floor below.

Consultant Stevens added that four Renkus-Heinz STX7/94 three-way loudspeakers are mounted on the bottom of the scoreboard. These provide additional coverage to the first two to three rows of courtside seating, and also serve as monitor loudspeakers for entertainment and performances on the court during timeouts and halftime.

This down-fill/court monitor system receives an independent mix from the house console. Stevens further explained that delay fill loudspeakers are used at the ends of the arena to cover the top few rows where video displays and team banners hang from the ceiling, blocking line of sight from some seats to the main arrays. Two Renkus-Heinz STX2/94s and two pairs of two Fulcrum CS121 subwoofers cover these seats at each end of the arena.

QSC and Lab.gruppen amplifiers power all loudspeakers in the facility, other than the Anyas, which are self-powered. “All of the QSC amplifiers are for the existing equipment in the concourse and other systems outside the bowl,” said Compo. “For all speakers in our install, we used Lab.gruppen 14000 Series for the subs, 10000Q Series for the Renkus-Heinz down-fills and C28s for the Renkus-Heinz delays.”

Challenges

Motorized hoists were specified for the main and sub arrays. Shown here are one of the two larger arrays covering the ends of the arena.
Motorized hoists were specified for the main and sub arrays. Shown here are one of the two larger arrays covering the ends of the arena.

Within the project installation time of around six weeks, there were several challenges. “We had to work around the arena’s schedule,” said Kuchero. “They still had events going on. So one of the challenges was to deal with the blackout dates where we were not allowed to be working in there. We had to be completely cleaned up and off the floor for a day. We may have had to do the same thing the following week for another event.”

“Part of the project was to have steel installed for the hoist system to raise and lower the clusters for the arrays,” added Compo. “Given the weight we were dealing with here, these were quite sizeable hoists, and we were working at 96 feet. That was probably the biggest challenge: how we were going to work at that height to install the system.”

The existing QSC Core DSP was retained to handle all system processing for the subwoofers, court fill and delay fill systems. Existing distributed audio in the concourse, dressing rooms, rest rooms and all the suites was reused and left as-is. System control is handled by the QSC DSP, while Anya system coverage presets are selected via the Resolution software.

New Digital Mixing System

Stevens specified a new digital mixing system for the project that adds flexibility for venue setup and use. A Yamaha CL3 desk in a road case allows operations to roll into the arena when an event warrants a mix position within the seating bowl. Multiple Ethernet connections (Dante primary, secondary and house network) and production intercom connections were installed at a flat floor location along the front edge of the upper level designated as the new primary mix position. Still, the mixing console can be set up at any location with access to the Dante network.

A Yamaha Rio 3224-D 32×24 Dante I/O box was added to the existing control room racks. All inputs and outputs terminate to a new Bittree 48-point patchbay located under the existing patchbay. Operations now can patch any of the existing analog lines to the Yamaha Rio for transport to and from the new mixing console via Dante. The existing PreSonus console remains in the control room and can be used as before, but now they can re-patch everything to the new console or even use both old and new consoles in tandem, if desired. Two additional Yamaha Rio 1608-D (16×8 Dante I/O) boxes in portable road cases provide inputs and outputs at any location with access to the Dante network.

The entire system now runs on the Audinate Dante Audio-over-IP (AoIP) platform, providing control and signal routing between the new Yamaha mixing system, the existing QSC DSP and the Anya loudspeaker arrays via standard Ethernet. This required some additional wiring. Belden and Whirlwind were specified for the new system installation.

“The main rack is located on the catwalk above the arrays,” Compo pointed out. “Each of the Anya clusters has three different types of wiring. You’ve got the Dante information going to the cabinets on Cat6 cables. You have the power for the Anya arrays because they’re self-powered speakers. Then you have the hoist control that goes to each one of the [hoist] locations.”

Two Belden Cat6 cables run from new HP switches to each Anya module (Dante primary and secondary) for a total of 80 network cables. New loudspeaker cabling was installed to drive the subwoofers, court fills and the new delay fills.

First Use

The new sound system’s first use was for the Oklahoma City Thunder’s preseason game against the Minnesota Timberwolves. Venue operations staff and the team communicated that they were pleased with the system and that they had received positive comments from fans after the game. Marsh and Stevens attended the game. Stevens said, “I’m really happy with the overall performance of the system. I heard remarkably consistent levels and response from the front row on the floor to the top of the upper bowl. I can’t wait to hear the system again when they’ve finished installing the acoustic treatments!”

Marsh offered, “This project was a dream. All the folks we worked with at the city and the Thunder were unquestionably committed to having the best possible sound quality in their arena. They demonstrated this in many ways, but especially by their willingness to do something out of the ordinary. I am thrilled about the success of this project and so proud to have been a part of it.”

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