Built in the 4th century B.C., the theater at Epidaurus in Greece remains a marvel of acoustical engineering. With a seating capacity of 14,000, the ancient performance venue uncannily delivers unamplified sound to the outermost row that's almost as audible as that which is heard by listeners near the stage.
SIA Acoustics' Sam Berkow at Temple Israel of Hollywood in Los Angeles.
Researchers at the Georgia Institute of Technology, reporting in the in April 2007 issue of Journal of the Acoustics Society, uncovered some of the theater's acoustical secrets. Most notably, the corrugated, limestone seats suppress the low-pitched frequencies of mumbling audience members, thereby limiting background chatter. Meanwhile, the limestone reflects and enhances the higher frequencies of the performance.
Interestingly, the architect who designed this extraordinary venue, Polykleitos the Younger, seemed simply to stumble onto these phenomena, based on his subsequent unsuccessful attempts to duplicate his acoustical acumen in other theaters using alternative seating materials, such as wood.
If he were alive and working today, Polykleitos would have a specially trained acoustical consultant to help him figure out what he did right the first time. If the sound still weren't right, he might kick the problem off to an audio systems integrator, hoping some magical DSP-based solution would do the trick. But would Polykleitos himself have a greater understanding—and interest—in building acoustics? That's questionable.
The fact is, architects need acoustics experts. Fostering a relationship between the two is key to successful AV projects—and a source of ongoing business opportunities.
“Acoustics is not a new science,” says Dr. Ning Xiang, an associate professor specializing in architectural acoustics at the Rensselaer Polytechnic Institute in Troy, N.Y. “Unfortunately, architecture schools don't tend to pay a lot of attention to it.”UNHAPPY CO-EXISTENCE
To better communicate with the architects it works with, SIA Acoustics creates its own renderings. Left is a typical detail for a double wall and an acoustically isolated space under the suspended ceiling. The rendering on the right shows isolated room construction with isolated walls, ceiling, and floor where an existing wall and ceiling slab are in already place.
That's not to say that architecture schools don't offer training in acoustics. Like a number of other institutions, Rensselaer, for instance, offers an intense graduate curriculum in building acoustics. Xiang says that more than 90 percent of the students who successfully complete the course load immediately find jobs in acoustic consulting. “That proves our society needs this profession,” he says.
Indeed, the acoustical consultancy profession is a burgeoning one, according to noted sound expert Sam Berkow, founder of New York–based SIA Acoustics. “Audiences in churches, sports venues, auditoriums, and theaters expect more now. They want quality sound,” he explains.
Still, the evolution of acoustician as a specialized profession within the architectural trade has resulted in an oft-unhappy co-existence: Call it “acoustical consultants and the architects who know they need them, but don't always love them.”
“Architects recognize they need to address acoustics in the design phase, but there are many who don't necessarily like working with acoustical consultants,” says Berkow. “They don't want to be constrained in their vision and their sense of form and function.”
Speaking what he calls “the language of the architect,” Berkow and his team detail their acoustical design concepts with their own architectural renderings, and often involve themselves on site during the entire construction of a building.
“We spend a lot of time on construction sites making sure things are built right,” he says.
Often, he explains, buildings will be designed with acoustic isolation problems, meaning sound leaks excessively from room to room. “The architect will say, ‘Fine, we'll add an extra layer of wallboard, and we'll make the wall thicker and heavier.' But they won't address the fact they have all this pipe work and conduit running through the wall, creating all of these penetrations.”
While Berkow has encountered plenty of builders who embrace working with him during design and construction, in order to avoid problems later, there are others who are reluctant. “Instead of approaching acoustics as a design challenge, they say, ‘We're going to do this anyway, and you're going to make it work.'”
“Historically, architects design a room then hire a consultant to come in and do the acoustics,” Berkow adds. “That philosophy has proven ineffective in places like concert halls, music studios, and places of worship. You don't design a room then do the acoustics. You design a room with proper acoustics.”