Sound for Any Given Sunday
New Gillette Stadium offers a system that “rocks” with added standards the look to the future
by Dan Garcia

I spent an afternoon last week sitting at the 35-yard line of the New England Patriots’ new Gillette Stadium, awash with U2’s It’s A Beautiful Day flowing through a $3.5 million sound system — 2000 speakers! — which makes this song better than I’ve ever heard it. Patriots VP Jonathan Kraft — the owner’s son and architect’s assistant — has just finished giving me a tour of the place and I’m soaking it in. And I think, I have seen the future of football stadiums and this is it.” — Peter King, CNNSI.com

One of the two large club spaces with reflective surfaces that warranted added intelligibility attention.

Privately financed at a cost of $325 million, Gillette Stadium in Foxboro, Massachusetts, is the first “state of the art” football stadium in New England, and it’s also the largest multipurpose entertainment venue in the region. Merging their respective talents, sound design firm Wrightson, Johnson, Haddon & Williams (WJHW) of Dallas and system installation firm SPL Integrated Solutions (SPL), based in Columbia, MD, implemented a distributed sound system for the stadium bowl and numerous satellite systems throughout the facility. Perhaps most notably, the sound design and installation were influenced to a great degree by a new requirement that could be a portal of the future.

Designed by architectural firm HOK Sport, Gillette Stadium is the new home of the NFL Super Bowl champion New England Patriots, in addition to hosting Major League Soccer’s New England Revolution and concert events. The open-air facility’s 68,000 seats are divided among a lower concourse that completely surrounds the natural grass playing surface, an expansive upper concourse on both long sides of the field and a luxury suite level.

WJHW Principal Ron Baker, who served as lead sound designer on the project, explains that officials pointed to Ravens Stadium in Baltimore, which opened two years ago, as the model for many Gillette Stadium elements, including sound. (The systems in Baltimore were also designed by WJHW.) This directed the design team to a distributed approach and also influenced some of the product selection choices.

The main rack in the control room, including control access to the networked Soundweb units and QSControl.

Baker points out the most interesting facet of this project is a requirement for “guaranteed” speech intelligibility for emergency evacuation purposes. The requirement, added after primary design work had been completed, applies to both the outdoor bowl system as well as two systems serving large indoor clubs behind the east and west main grandstands. Baker sees the intelligibility requirement, based upon International Electrotechnical Commission (IEC) standard 60849, as a harbinger of the near future. “This is something that’s going to be a part of fire codes for stadiums in the U.S.,” he notes. “It’s not yet mandated, but was required by governmental regulations as a result of variances granted on the project. In terms of enhancing safety procedures, it’s a very good thing.” MONDO MODELING WJHW regularly uses EASE modeling in the design process to aid in predicting system performance and coverage, including specific intelligibility factors such as %ALCONS and RASTI.

The additional requirement, loosely defined as the ability for the system to produce consistent 95 dB (A-weighted) levels throughout its entire coverage area while attaining specific “high” marks in intelligibility stated in IEC 60849, placed further emphasis on the modeling/ simulation process.

After the EASE predictions were formulated, this data was evaluated and confirmed with the Bose Modeller program. Then CATT, a more acoustically oriented program, was utilized to further evaluate/confirm the predictive simulations. Thus, all three programs played off each other for thorough comparison and verification.

“We were confident in meeting requirements in the stadium bowl, having done these systems many times in the past and knowing, especially with a distributed system, that there’s plenty of headroom with respect to level,” Baker says. “The indoor club spaces presented a bit more of a challenge, being large in volume and fairly reverberant, combined with relatively high ambient noise levels when they’re full of people.”

Pat McConnell (left) and Jack McCallum going over system plans at the Soundcraft K2 console in the control room.

Three stories high and bounded on one side by full glass walls, the clubs required systems providing a higher “Q” (focused sound) than normal, in order to deliver the necessary intelligibility. As a result, WJHW selected an unusual ceiling-mount loudspeaker, the Eastern Acoustic Works (EAW) CP621, for this application. The CP621 is a two-way, coaxial design, with six 5.25-inch woofers that are concentrically arrayed around a 1- inch-exit compression driver on a constant directivity horn offering 60 degrees conical coverage. Two more 5.25-inch woofers are coupled to the horn, and the enclosure is vented. The package combines to supply much more intense output than usually supplied by ceiling loudspeakers.

To further insure sound pressure levels and intelligibility exceeding the specification, approximately double the amount of loudspeakers “normally” required for an application like this were installed. In addition, compact Tannoy CMS50T loudspeakers were mounted in corridors bordering each club’s upper level.

“There are more loudspeakers in this club than anything we’ve done like it previously,” Baker notes. “We sought 10 dB above an 85 dB-A ambient level, and this was exceeded, with uniform coverage and clarity. Testing confirmed this performance.”

After SPL installed these loudspeakers, in addition to hundreds more in the stadium bowl, a considerable effort then commenced to verify that intelligibility standards were being met. Over a two-week period, Phil Nelson of WJHW (now senior engineer with Electro Acoustics & Video of Fort Worth), assisted by WJHW’s Edward Parker, performed 500- plus measurements at numerous locations. Each designated location was subject to at least five individual measurements, with the average of each set of measurements required to meet or exceed the specified standards.

A view of the loudspeakers covering upper and lower seating areas of the west grandstand.

Nelson and Parker used a new Gold Line STI-CIS system for quantifying speech intelligibility. This package employs Gold Line’s DSP30 analyzer platform along with a STI-PA signal CD developed by TNO Laboratories of the Netherlands as the international measure of speech intelligibility. With the STI-PA signal playing in the system under test, the DSP30 analyzer is capable of producing the STI, which is then converted to the Common Intelligibility Scale as specified in standard 60849. Multiple measurements can be captured by relocating the DSP30 while the STI-PA signal continues to play. GUARANTEEING AUDIO SPL Project Manager Pat McConnell explains the other portion of the emergency evacuation criteria applied to this system. “Intelligibility assurance is important, and it’s equally vital to do everything possible to guarantee audio signal can be delivered, particularly in emergency situations when conditions may not be optimal,” he says.

All conduit and cable chases were routed through fire-rated areas of the stadium to afford as much protection as possible. Data and audio signal are largely distributed via fiber optic, with copper backup for certain aspects deemed crucial enough to require back up.

BSS Soundweb 9088i digital signal processors provide system-wide signal processing parameters in addition to routing audio signal and control data. Network control of 9088i units both at the control room (suite level in the north end zone) and at two distributed equipment rooms (centrally located on the main level along each side of the bowl) is attained via a PC at the mix position.

Tough coverage regions in both end zones are handled by loudspeakers mounted on poles.

Another 9088i on the network, located at the stadium’s emergency command center is performing more specific functions. This unit receives a 20 kHz test tone that travels via the network to all other Soundweb units. At each processor location, this signal is sampled, verifying the presence of “good audio” at each unit and the test signal is “stripped off” before being converted back to analog. Each Soundweb also has an opto-isolated output feeding an LED panel at emergency command that supplies instant performance verification. (BSS fiber interfaces prove handy in transporting signal and data via the fiber optic lines.)

If this processing/routing network happens to fail for any reason, an “ultimate bypass” allows a microphone feed at emergency command to route, via copper backup, directly to a single 9088i unit at each amp rack. This signal is then delivered to the power amplifiers.

One other caveat: Because it’s been proven that the perception of intelligibility increases when the person speaking can be seen, a camera at emergency command has been set up to transmit video signal of the fire commander to the stadium’s two large video screens (one at each end of the bowl), as well as to all televisions in the luxury suites.

DOES IT ROCK?

In addition to intelligibility, Patriots’ officials also had keen interest in providing fans with a “stadium that rocks.” With hundreds of distributed full-range loudspeakers carefully aimed to focus energy directly on the audience in the bowl, this request could be met fairly easily.

“We were looking for peak levels in the 105 dB range at all seats, and as a matter of course in correctly designing and installing these types of systems, this can be met,” Baker says. “Without dedicated subwoofers, you don’t quite get concertlevel performance, but it certainly is sufficient in presenting full, dynamic sound.”

Stadium officials’ emphasis on sound quality also meant WJHW was brought into the project at an early enough stage to have influence in obtaining adequate loudspeaker mounting positions. This is an essential - yet sometimes overlooked - element of a successful distributed stadium system, particularly with respect to locations in the upper deck and on grandstand facings, where advertising signage can be given top priority.

Working closely with the architect, positions were mapped out using existing structure elements, with the exception of three concourse regions in the end zones. Architecturally, these regions were devoid of any structure and thus were outfitted with steel poles to accommodate sufficient loudspeaker positions.

Gillette Stadium ready to host its first-ever NFL game.

“In the upper deck, which is normally the single most difficult location, the architects were able to extend the lighting truss over the seating enough to provide us with suitable mounting points,” Baker explains. “Not only did this work for our needs, but it also created an aesthetically pleasing visual element as well.” Coverage to the upper deck is primarily supplied by clusters made up of three loudspeakers, mounted to the lighting truss and spaced approximately 45 feet apart.

Each cluster includes an Eastern Acoustic Works (EAW) AOS130 loudspeaker, supplying the highest output and covering up to the front row and several rows behind.

A transition is then made to coverage by an EAW MK2194 (90 degree by 40 degree pattern) loudspeaker, which handles seating rows leading up to directly beneath the truss. Then an EAW MK5194 (also 90 degree by 40 degree pattern) picks up coverage to the very last seating row.

Intermediate clusters made up of an MK2194 and an MK5194 are spaced equidistantly between the main clusters. With their horns rotated to provide 40 degrees horizontal coverage, they fill the nearer field and down fill areas where main cluster coverage tapers off.

EAW KF750 concert loudspeakers mounted to the end zone facing and walls provide high-output coverage.

All of these loudspeakers are twoway with passive crossovers, and all have been utilized in several past distributed stadium systems by WJHW. An interesting footnote: the AOS130 was first co-developed in 1995 by EAW and WJHW for the Olympic Stadium in Atlanta (now Turner Field). A somewhat similar approach is utilized for lower concourse grandstand coverage, where EAW MQV2364e three-way loudspeakers are mounted to the upper grandstand facing, approximately 55 feet apart, blanketing the front row up to almost directly beneath. From there, coverage is picked up by more EAW 5194’s mounted on the underside of the grandstand, with the back four seating rows covered by compact Renkus- Heinz TRC81 loudspeakers. Mounted directly behind the MK5194’s, these are positioned to fire “backward” and are the only bowl loudspeakers driven on 70-volt lines.

Seating in both end zones required higher output due to longer mounting position locations. Several EAW KF750 concert loudspeakers, attached to structural facings, cover both of these regions. And, steel poles were installed in the corners of the end zone concourses to accommodate either MK2194 or MK5194 loudspeakers, depending upon individual coverage requirements in these regions.

DETAILS TO SUCCESS

SPL’s McConnell notes that in complex, large-scale projects such as this one, the contracting firm does a load of pre-engineering work in the months leading up to actual system installation. Success is in the details as components are readied, racks pre-wired to the greatest extent possible, documentation reviewed and refined, etc. Don Alberg, senior design engineer for SPL, proved to be the driving force behind much of this vital work on this project.

Arriving on site in early September of 2001, McConnell spent more than a year working long days to coordinate the installation crews, working out details and logistics with the numerous other vendors and contractors on site and dealing with lastminute problems that invariably come up with a project of this scale. He also interfaced with WJHW Senior Consultant Jack McCallum, who served as the design firm’s primary on-site point person. “You can’t do these projects on remote control, because every day there’s something that comes up that has to be dealt with immediately,” McConnell notes.

The lighting truss extends out over the upper deck seating, creating more optimum mounting positions for the clusters.

In addition to establishing the advanced fail-safe aspects of the system previously described, another challenge proved to be mounting the bowl loudspeakers, which had to be done after seating was installed. SPL designed custom brackets, fabricated and tested ahead of time, attached to mounting locations in the bowl. Later, scaffold was quickly erected at each location and loudspeakers raised into position with a winch, where the crew could bolt them to the brackets, quickly and simply, using only wrenches. All loudspeakers are driven by QSC CX Series amplifiers, split between the two distributed equipment rooms, with companion QSControl, running on the same PC as Soundweb software in the control room, serving as a remote amplifier/loudspeaker maintenance and diagnostics tool. A Soundcraft K2 40-channel console holds the front/center position in the control room, flanked by dual JBL Control Series loudspeakers that serve as monitors for the enclosed space.

MOVING FORWARD

Sound reinforcement quality at football stadiums continues to improve due to the increasing skills of the audio/acoustical consultants designing these systems as well as the contractors who install them, with both taking advantage of steadily advancing technology. This project proved no exception.

“We’re quite pleased with the final results here, and the clients have expressed their satisfaction,” Baker says.

“It’s gorgeous. It almost makes me want to go out and buy a pair of the few remaining club seats.” - Peter King

Dan Garcia is an independent audio veteran and parttime journalist.