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Adding Variables

Adding Variables

Electro-Acoustic Enhancement Systems Take On New Applications In A Variety Of Venues

The Nokia Concert Hall in Tallinn, Estonia uses Meyer Sound’s Constellation to vary the reverberation time from one to over two and a half seconds.

This is not your old high school auditorium where a lone onstage microphone sent out screeches and squeaks and no intelligible speech could be discerned in the far reaches of the back rows. Electro-acoustic enhancement, loudspeaker technology, and the push for rooms that can accommodate multimedia programming have significantly altered the auditorium landscape.

The first of these tools, enhancement systems, also known as variable acoustic systems or active acoustics systems, need to be carefully selected for the right environment, explained Jonathan Laney, collaborating consultant at Threshold Acoustics in Chicago, IL. “These systems can be used in three ways. One is as an element in sound design within theater and dramatic presentations, another is to create a concert hall environment in a room that wasn’t designed to support it, and, of course, to create an enveloping listening experience in an outdoor setting such as what was accomplished at Millennium Park in Chicago.”

There are still very basic physical, acoustic, and noise control parameters that must be thoughtfully designed for these systems to work, he elaborated. “You can’t remove bad acoustics but you can create early reflection patterns and greater reverberation in a room. If there are specific specular energy reflections or too much reverberation you won’t change them by using enhancement systems. The room has to be well behaved in order for these systems to enhance what is already the existing acoustic signature.”

The Name Game
Where there used to be hidden enhancement solutions from a few boutique custom manufacturers, now there are more available. “We’re moving forward with new products that are scaled for the various markets we serve—which include performing arts, sports facilities, houses of worship, conference and training rooms, and rehearsal spaces, to name a few,” noted electro-acoustic enhancement pioneer Steve Barbar, who is wearing a new hat, that of principal at E-coustic Systems, the recently rebranded LARES company. “We’ll be introducing the new hardware at AES.”

The small- to medium-sized auditorium landscape is also changing, Barbar said. “They need to support a wider variety of programming. A good example is the Sweetwater Performance Theatre [in Fort Wayne, IN], a merging of green technology and audio used fundamentally for training that also needs to support musical performance.”

The multi-use trend takes varying paths. At the Smithsonian, a 400-seat auditorium primarily used for lecture now hosts a Steinway-sponsored concert series and a film series, broadening its programming scope to create more interest and additional revenue from media presentations.

Additionally, “the Adelaide Festival Center Theater will be hosting a new film series, and we will reconfigure it,” Barbar noted. “The advantage is that the LARES system hardware and loudspeakers are already in place. No additional installation is required and the changeover from orchestra to film and back can happen overnight with little cost.”

Other LARES venues that expanded their horizons include the Carmel Sunset Theater in California, which will be adding film, as well as Guadalajara’s Auditorio Telmex, which recently hosted the Guadalajara Film Festival. “A lot of independent films have regional appeal, and these venues are ideal for showing them,” Barbar observed. “For many years the Toronto Film Festival has utilized the LARES system in the Elgin Theatre. Soon, the newly refurbished Sony Centre for the Performing Arts will also use its LARES system to help support the festival. Everything is leaning toward media presentation and the concept of programming a venue for a wide variety of events.”

Venue size is all over the map, he said. “Our smallest auditorium installation is the Wantage Civic Center in the U.K., which seats approximately 250. In contrast, we have a system in the largest auditorium in the world which is the 21,000-seat LDS Conference Center in Salt Lake City, UT.”

The largest auditoriums may have to cater to new technology such as 3D film, he noted. “This may not be immediately available in smaller auditoriums because of projection costs, but for larger ones, it’s a consideration. Within a few years equipment will become more affordable as the cost for newer projection technology comes down. The emergence of 3D media with new multichannel surround sound formats in the consumer market will help top bring these technologies to smaller auditoriums. For audio integration, however, this means infrastructure for 10-channel surround sound will need to be accommodated.”

Call It Active
“We refer to this technology as active acoustics,” said Steve Ellison, applications director for digital products, Meyer Sound. “Active refers to the process of microphones, processing, amplifiers, and loudspeakers adding acoustic energy to a room.”

Active acoustics can change a room in both subtle and dramatic ways, he explained. “In auditoriums and theaters, having dry acoustics is good for spoken word but if you break into song with a chorus, you’ll wish the room were more reverberant. Theater has always been about transporting you to different places. Active acoustics is one technique to help achieve this.”

Additional applications for active acoustics include worship and education. “Music education in auditoriums is huge,” Ellison said, “and there are thousands of secondary schools and colleges wanting to build or upgrade their facilities to gain a more efficient use of what they have, and it makes good dollar sense. Music programs typically include band and choral programs, and sometimes orchestra.

“For example, Spring High School in Spring, TX has a particularly strong choral program and it utilizes our Constellation active acoustic system in its auditorium both in the seating areas and on stage. We created a setting that acoustically transforms this auditorium into something more like a reverberant church with an RT of 3.5 seconds. The school believes this gives them an edge when they rehearse for choral competitions, which in Texas are almost like another contact sport. Ten years from now, these systems will be extremely common in the education segment.”

Even auditoriums used for spoken word may need a little help, he added. “In many of these rooms, Constellation will add early energy from stage to house, whether for a lecture, acting class, or play, making it a little easier to reach more people in the room, and some cases two directions. In smaller 200- to 300-seat auditoriums it can be hard to carry on a question and answer format where a wireless mic is passed around the room, so we’re seeing the system used for voice lift applications to facilitate discussion in these smaller venues.”

The Yamaha AFC System in the 920-seat auditorium at Victor High School in Victor, NY has four presets: Orchestra, Chamber, Chorus, and Normal.

Integrators need to be careful about architectural integration with active acoustic systems. “The control system aspect is fairly simple; however even the 700-seat auditorium in Spring uses 24 microphones and 60 loudspeakers,” Ellison said. “Integrators need to make sure that the transducers are properly installed in positions specified in the system design. We created an installation manual to help integrators with common issues. Also, Meyer Sound provides onsite tech support to assist with the installation and to collect data that allows us to pre-program parts of the system before we arrive onsite to tune. Tuning involves calibration followed by voicing. We involve the stakeholders in the voicing process as much as possible, including musicians, operators, and consultants. This process enables our clients to get the most out of their newly variable acoustics.”

Increasingly, auditoriums are becoming theaters at the secondary and college level, adding sound design to the list of requirements for the system. “Our Audio Show Control technology is integrated into Constellation,” Ellison remarked. “This allows the end user to add other audio inputs to the system and route them to groups of loudspeakers in the room. And for the intrepid theater sound professionals, they can learn to literally fly sounds around the room using our SpaceMap technology.”

The Nokia Concert Hall in Tallinn, Estonia uses Constellation to vary the reverberation time from one to over two and a half seconds. “The acoustics are consistent throughout the room,” Ellison observed, “and sounds very natural because no matter where you are in the room, whether you clap or sing, the room reverberates as it would if the reverberance were achieved through physical acoustics. This gives the room the flexibility to host nearly any event imaginable.”

Reverb Yourself
Yamaha’s Active Field Control (AFC) technology uses a regenerative system to achieve the most natural sounding reverberation. The goal of the AFC reverberation element in the enhancement system is to create a uniform sound field in the space, said Lon Brannies, consultant and AFC marketing manager.

“This sound field is easily and economically achieved with conventional loudspeaker systems with little need for high directivity, ultra-wide bandwidth, or other newer designs,” he said. “Requirements for high directivity in an electro-acoustic enhancement system are usually minimal. Energy exchange for the stage uses loudspeakers similar to reverberation. An AFC early reflections element does use loudspeakers with somewhat higher directivity. Some systems have need for extended low-frequency response. AFC technology uses conventional subwoofers for this application in conjunction with other elements.”

Small house of worship or high school auditorium projects are usually at the entry level for an AFC solution, falling into the 450- to 900- seat size space. Typically, they are very budget conscious and reflect the simplest of design criteria.

“Electro-acoustic solutions are slowly becoming more widely accepted as they achieve better market penetration and as more audiences have an opportunity to hear them in performance,” Brannies said. “Larger spaces, up to about 2,000 seats, are now online, although there are a few even larger project examples. The reason is the wider variation permissible in the reverberation time curve relative to the construction budget.”

Acceptance of sound quality changes and budgetary issues present the major limitations in the current iterations of electro-acoustic enhancement system design. As manufacturers solve these problems, he said, the industry will see greater market penetration and inclusion of this technology. Clients are starting to accept the budget changes needed for such systems.

“Yamaha sees the greatest push for AFC technology in high school, community, and university auditorium projects where the space is used for a wide variety of musical styles but the players are more unsophisticated in their musical abilities,” Brannies said. “As musical performance ability achieves higher capability, there is stronger client desire for traditional acoustical solutions to reverberation problems. Consequently, auditorium space for professional orchestras or opera companies usually seeks purely acoustical solutions for such problems.”

Threshold’s Laney said the challenges and excitement center on chances to change acoustic signatures. “What is the expectation for a high school auditorium: is it a concert hall or simply what it always has been? Personally, I think these systems provide a fantastic opportunity for a sound designer to change an acoustic space for a theatrical or dramatic performance.”

If a room is already live, he said, it can’t easily be changed into an intimate experience, but if it’s intimate, various acoustic signatures that are larger or more cavernous may be created with these systems. “You can take a small, intimate club and make it more enveloping,” Laney said. “It all comes down to budget; manufacturers are looking for new markets and the ability to sell more product. For me, as a consultant, these systems are tools for the right client and space. Whether for new construction or renovation, one has to weigh both the expectation of the client and the performers’ expectations, and whether there is an architectural solution or loudspeaker or technology solution. One is not necessarily better than the others.”

Margin Builder
Growth in electro-acoustic enhancement systems will increase infrastructure in both the design and construction phase of any project in order to accommodate multimedia presentations. “The demand for multi-channel audio is partly driven by the explosion of sound in consumer gaming, computer, and home theater projects,” said Steve Barbar of E-coustic Systems. “This creates heightened expectations for audio delivery in auditoriums.”

Karen Mitchell is a freelance writer based in Boulder, CO.