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.
The burden of architect's “fix it in the mix” mentality, the idea that any acoustical deficiencies can be addressed after the building goes up, often extends to AV integrators.
“Acoustical consultants are brought in for large projects like concert halls, but on smaller projects, it's often the sound system contractor who needs to take care of acoustical problems,” says Brad Nelson, owner of Kennewick, Wash.–based Sound Solutions Northwest, a company that specializes in the house of worship sector. “And often the mindset is that the sound system itself will fix things. That's where we get into a lot of problems.”
Nelson and others believe architects' disregard for acoustics can be blamed, at least in part, on advances in audio electronics—not to mention modern building materials and techniques.
“With the advent of modern sound systems, acoustical considerations have really gone by the wayside,” says Bill Schafer, an engineer who has overseen a number of loudspeaker installations at Los Angeles International Airport for Hawthorne, Calif.–based Direct AV. “If you look at churches that were built 100 years ago, there was no sound system, and the building had to be designed so that voice audio could project unaided throughout the facility. These older buildings tend to be a little more diffuse in terms of their reverberation—you don't find a lot of flutter echo or hard slap. You tend to find a lot of columns or other detail in the room that breaks up sound. There's also a lot of wood in these places, which is a lot better [for sound quality] than drywall.”
For his part, Nelson concedes that ornate wooden structures may not be practical construction considerations anymore. “It's certainly a lot cheaper and easier to work with Gypsum wallboard and large, flat surfaces,” he notes. “That's kind of the default way of building these days, and from a construction and appearance standpoint, that's fine. But from an acoustic standpoint, that can create challenges in certain situations. We often find ourselves having to look for some creative solution to put a Band-aid on things.”
Within modern buildings, flutter echo—the repetitive reflection of sound waves caused by hard, flat parallel walls or floors and ceilings—is a common problem. In many cases, this issue can be effectively addressed after the fact with the strategic placement of sound-absorbing materials, such as foam or ceiling tiles.
Meanwhile, recent technological advances—such as digital signal processing, which enable loud speakers to precisely direct sound waves to places where they don't bounce around—have created other options for integrators who need to address problem audio environments.
“But there's no amount of DSP that's going to alleviate things like high reverberation time or flutter echo between parallel walls,” Nelson notes. “Unfortunately, once the sound leaves the loudspeaker, the room acoustics take control.”
If architects aren't aware of acoustics, and just what modern AV technology can and can't do to enhance them, they can be forgiven, says Keith Willis, co-owner of Innovative Theaters, an integrator of high-end residential AV systems, based in West Hollywood, Calif.
Acoustics is an involved science, Willis says, and architects are now designing buildings that often employ state-of-the art electronic audio enhancement—technology that is often too specialized for them to fully understand.
“You have to be well versed in the products to understand acoustics,” Willis says, noting that many of Innovative Theaters' projects are new homes in which he and his business partner work closely with the architect.
“And there is no global rule of thumb to acoustic design—it's a lot of trial and error, and also an understanding of what the sound system is capable of. Our industry has grown so fast, there's no way for an architect to have a finger on the pulse of all this stuff. They shouldn't have to know this stuff. But at the same time, architects must recognize that acoustics [isn't] their area of expertise,” Willis explains. And seek expert help.
Daniel Frankel is a freelance writer based in Los Angeles. He can be reached at firstname.lastname@example.org.