Here To Stay
Concert Sound Quality as a Permanent Fixture
Stadia - October, 1999
The newest and best loudspeaker systems always could be seen and heard in large
sporting venues. But they were largely restricted to the 'visiting team'. They
were brought in by the sound rental company, set up for the big-name concert,
and taken away shortly after the last encore.
Typical installed systems, although well suited to announcing the team roster, simply were never meant for high quality, high-level music reproduction. In other words, you would not really expect a football stadium to use exactly the same loudspeaker systems as you would find, for example, at the San Francisco Opera House or on tour with Celine Dion.
But that expectation is changing in response to the changing expectations of sports fans. Today, those who attend a sporting event expect more than just a game; they expect multi-sensory excitement, an experience with high entertainment value.
With this changing reality in mind, two sporting venues in the state of Florida have recently installed leading-edge audio systems that incorporate the latest advances in loudspeaker design. Here will be found permanently installed loudspeakers that are exactly the same as those at the San Francisco Opera and over the stage during Ms.Dion's recent concerts.
The NFL's latest'theme park'
Tampa Bay's Raymond James Stadium is the new crown jewel of National Football League facilities. Named after a sponsoring investment firm, the stadium cost US$168 million, seats 65,000 (expandable to 75,000) and covers 1.92 acres. The Tampa Bay Buccaneers are the principal tenants, but the facility is also home field for the University of South Florida football and the Mutiny professional soccer team. The stadium was designed by HOK Sport of Kansas City and is operated by the Tampa Sports Authority.
Tampa is a mere 84 miles from Disney World, a place where exploding entertainment technology has reaped soaring attendance figures and enviable profits. Team owners and stadium operators are taking notice, giving rise to the emerging phenomenon dubbed 'sportainment.' Raymond James Stadium has taken this trend to a new level of sophistication.
One striking example is 'Buccaneer Village', an end-zone attraction featuring a full-scale pirate ship replica surrounded by rustic shops and concession stands. But even when seated in the grandstands, fans are entertained by two wide-screen - electronic scoreboard video displays, with the content supplied by a staff of 30 technicians housed in a full-blown video production and computer effects studio.
The displays are the largest of their kind to support the new High Definition Television (HDTV) format.
High-definition audio
To support the visual images, and help stir up fan excitement, the stadium designers called for a sound system that could deliver power and clarity to rival that of a concert touring system. This was not an easy task considering the layout of the structure.
Power and clarity are most easily achieved when loudspeakers are placed near
the spectators, preferably in front of them. (For psycho-acoustic reasons, you
want to avoid projecting sound from behind seating areas.) Therefore, the ideal
solution is a distributed system with many loudspeaker clusters placed all around
the stadium. This works well in facilities with domed roofs or partial canopies,
and with overhanging balconies, all of which provide mounting points for loudspeakers.
But like many new Sunbelt stadia in the USA, Tampa Bay is a wide-open design.
A front-firing distributed audio system would require the mounting of speakers
on poles between spectators and the field - an unacceptable solution because
loudspeakers and poles would block sightlines and interfere with TV camera angles.
The only alternative, then, was to mount a single loudspeaker cluster at one end of the stadium to cover all the seating areas. Though conceptually simple, the single source approach is fraught with technical difficulties in a stadium of this size. The loudspeakers must cover all the seating areas with powerful, high fidelity sound, yet at the same time keep sound levels low on the playing field and avoid hitting reflective surfaces that could cause problematic echoes.
The long (audio) throw
This daunting task was first placed in the hands of Gary White, an acoustical
and sound system consultant for the firm of Wrightson, Johnson, Haddon and
Williams of Dallas, Texas. Earlier, White had designed similar end-zone
systems for two other NFL stadia in Charlotte, North Carolina and Jacksonville,
Florida. Although he confronted similar acoustic problems and budget restraints
at Tampa Bay, he nevertheless wanted to find a way to boost power and improve
fidelity, particularly at the far end of the stadium, a throw of over 700ft.
White first drew up a bid specification based on separate speaker and amplifier technology, but all bids came in over the allowed budget. One of the bidding contractors, ProSound of Miami and Orlando, then suggested to White that he write a new specification based on self-powered loudspeakers. Self-powered loudspeakers have won a loyal following over the past five years among concert touring sound companies, Broadway-style theatres, opera houses and other music-oriented venues. But they had never been tried in a large outdoor stadium.
Self-powered loudspeakers are exactly what the name implies: the amplifiers
powering the speakers are mounted inside the cabinets. This has a number of
advantages. First, the amplifiers can be designed for optimum performance with
that particular loudspeaker, rather than compromising on some performance aspects
in order to accommodate a wide variety of loudspeakers. Second, the necessary
signal processing (signal splitting, equalization and time delay) can be custom-tailored
for the loudspeakers and placed inside the cabinet. Third, this design eliminates
long audio cables between amplifier and speaker, a powerful benefit considering
that long speaker cable runs degrade high frequency performance. Self-powered
systems take up less building space because bulky amplifier racks are eliminated,
and, finally, installation proceeds more quickly because fewer components need
be installed and calibrated.
Scepticism overcome
Although open to the idea, White was sceptical at the outset, primarily because he was nervous about the prospect of placing a self-powered loudspeaker system in a semi-exposed outdoor setting about 150 ft above the south end scoreboard. The 20 x 60 ft steel speaker enclosure has a roof, but the front is an open wire mesh screen. It should be remembered that Tampa Bay simmers in a semi-tropical climate: rainfall is often more horizontal than vertical, humidity is constant and lightning strikes are frequent all year round. White was concerned about placing amplifiers and other electronics normally housed safely indoors in such a hostile environment.
Accompanied by engineers from ProSound, White visited Meyer Sound
Laboratories in Berkeley, California for a first-hand look at some new powered
systems. After examining the fail-safe weatherproofing techniques and listening
to testimony for other users on extremely low failure rates, White felt confident
enough to go ahead and specify the first large scale, outdoor self-powered system.
Included in the design were two revolutionary new Meyer products: the SB-1
'Sound
Beam' and the PSW-6
self-powered cardioid subwoofer system.
An acoustic'spotlight'
The Sound Beam solves a problem that plagues all single-point systems in large outdoor venues: how do you project mid-range and high-frequency (treble) sounds to the far corners without splitting the eardrums of nearby spectators? The only way to do this to use a speaker with extremely narrow beamwidth - essentially an audio spotlight. Unfortunately, conventional horn-based loudspeakers have a limited ability to focus sound over long distances; a beam width of about 30° is the best they can do. At Tampa Bay, however, a 30° beamwidth would demand a choice between reducing response in the far corners or generating bothersome reflections off large flat surfaces above the seating areas.
Sound
Beams solve the problem with revolutionary audio technology. Instead
of using the conventional horn, the Sound
Beam employs a parabolic reflector (similar to a satellite dish) that
tightly focuses the sound within a ten-degree beamwidth. With this new audio
'spotlight', White was able to design a four dish configuration that could cover
the far corner areas with no echo problems.
Another problem confronting 'sportainment' systems is control of the bass frequencies. Contemporary music and sound effects depend on ample bass power, but directing low frequency energy is problematic. The bass generated by conventional subwoofers is omni-directional: it goes out in all directions with equal energy. This can cause unwelcome cancellation effects, with too much bass in some seats and not enough in others. Also, an equal amount of bass energy goes out the back, beyond the stadium, where it could annoy neighbors who do not have to be immediately nearby, considering the power of new systems!
Again, Meyer Sound solved the problem with another patented innovation, the PSW-6 self-powered cardioid subwoofer system. It employs the same principle as directional microphones, but in reverse. Instead of conventional omni-directional radiation, the PSW-6 directs sound mostly out the front, with more than four times as much energy projected forward as toward the rear.
The Tampa installation employs eight PSW-6 subwoofer systems, each housing two 18in and four 15in speakers and four 620W power amplifiers.
The remaining Meyer Sound speaker complement comprises eight MSL-6 cabinets, two MSL-4 cabinets and four CQ-2 cabinets. These are all full range, self-powered systems, differing primarily in size, power and coverage patterns.
The payback
Although the powered speakers solution was more expensive when calculated on a per speaker/amp channel basis, the payback came when the system was installed. Under the direction of ProSound's Stan Hutto, the work proceeded smoothly and quickly, using far less time and less wire than needed for conventional systems. In fact, the Meyer Sound end zone system was ready to go before the indoor equipment room was finished! (Conventional amplifiers and speakers were used for concourse areas, restrooms and suites.) This allowed final aiming and calibration to proceed ahead of schedule. Instead of the last-minute panic typical of many such installations, Pro-Sound had the Tampa main cluster completed and tested almost a month before the Buccaneers first home game.
The results were satisfying to all ears. "We were immediately struck by the power and clarity of the sound," says Stan Hutto. "We put on CDs and walked around the stadium, having a ball just listening. Even when we were out in our trailer, about 900 ft distant, we could clearly hear every song playing."
After the first season of play, evaluations from the system's owners were equally enthusiastic: "The clarity is just outstanding," says Bud Johnson, operations manager for the Tampa Sports Authority. "The difference between this system and the old one at Houlihan Stadium is just incredible." Adds Bill Hand, project manager for TSA: "We are very satisfied with it. It has received very good reviews from the public and has far greater capacity in terms of loudness. We've had to ask the team's operators to exercise some restraint! "
In addition, the system has proven quite reliable and experienced no weather-related failures despite exposure to rather severe conditions. "They had a mini-hurricane up there for a few hours last winter," says Stan Hutto, "with three inches of horizontal rain and 80mph winds. They were in the middle of an event, but the full system kept on working until power to the city grid was knocked out. Audio fell back to emergency announce capability, then came back up fully when power was restored." The reliability demonstrated by Tampa's system seems to have removed Gary White's last reservations about installing self-powered systems outdoors.The HOK expert recently specified an even larger system, based on Tampa, as an option for the renovation of a 100,000 capacity collegiate stadium in the Midwest.
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| Claim to fame: Drawing inspiration from fellow Florida attraction Disney World, the stadium is 'sportainment' in its highest form: a full scale pirate ship graces one end-zone with skull-and-crossbones throughout | |||||||||||||||
An indoor example
The first major installation of a self-powered system at an indoor arena was another ProSound project, this time at the University of Florida's O'Connell Center, located in Gainesville.
The O'Connell Center is a domed sports complex which houses a 12,000-seat basketball/multi-use arena, as well as a swimming pool, practice courts and various exercise and training facilities. In 1998, as part of an US$8.5m renovation, the original 18-year-old pressurized soft dome was replaced by a new steel roof, and new lighting and sound systems were installed in the main arena.
This self-powered system was designed as a cooperative effort between ProSound president Rod Sintow and Topper Sound Associates. The specification called for 10 MSL-4, five CQ-2 and four CQ-1 full range cabinets, augmented by six PSW-4 powered subwoofers. The loudspeakers were arranged in four clusters, hung in the center of the arena and directed out toward the four seating zones as well as down onto the floor.
The Gainesville installation highlights another advantage of self-powered systems, according to ProSound's project manager, Bobby Greene. "Each speaker can be turned up or left mute individually, or even be sent a different audio signal," he points out. "Many conventional distributed systems have multiple speakers all wired to the same amplifier channel, which limits flexibility in setting up a system for different events."
In the O'Connell Center, ProSound installed a computer-controlled BSS Sound Web system that (among other functions) - controls signal routing. Working with O'Connell Center staff, ProSound programmed eight presets in the Sound Web to cover different event types. With a click of a mouse, an operator can instantly reconfigure the system, turning speakers on or off and setting levels to best suit the event.
As was the case in Tampa, the new indoor system in Gainesville has noticeably boosted the level of fan excitement and involvement. "I've heard from the operators that the sound has never been better," remarks Greene. "They are using a lot more music and sound-effect bites. It's much more like what you would expect at a professional NBA game. It's one of the ways you get people to come back. Certainly you hope to have a competitive team, but you also give the fans entertainment value along with the game."
Not better, just more
As demonstrated in Tampa and Gainesville, audio technology for sports facilities has taken a step forward with the advent of powered systems. Permanently installed speakers no longer need envy (were such feelings possible) their counterparts in touring systems. In more and more cases, speakers on the 'home team' are fully equal to those brought in by the 'visiting team.'
However, this does not mean that touring sound rental companies will go out of business. Concert requirements are different and usually the systems are larger because more power is needed. It would not make sense for most facilities to permanently install systems of such magnitude.
Nevertheless, although permanent systems may be of a lesser size, the advantages of self-powered cabinets are leading more facilities to consider 'concert quality' audio installations. So today, for example, if Celine Dion comes to the Tampa stadium, her touring system will not be fundamentally better than the one over the scoreboard. Just more of the same.
