By Dan Daley
If architects have had to become more sound-savvy in recent years, they can thank Steven Spielberg and George Lucas. Star Wars changed more than the movies: That film series, which made THX a household name, combined with the advent of digital audio to forever change the expectations for sound. Fortunately, the technologies and tools to meet those expectations keep evolving.
Auralization
Reliably predicting what sound will do before the foundation is even poured is increasingly possible, thanks to a new generation of acoustical modeling software programs that define a new subscience in acoustics called auralization. A leading-edge iteration of this is from Swedish developer Catt Acoustic (www.catt.se). This software produces octave-band echogram-based predictions based on a 3-D CAD model of a room. Frequency-dependent material properties (i.e., absorption, diffusion) are assigned to room surfaces and frequency-dependent source directivities are assigned to sound sources. From this information, a variety of numerical values, such as speech intelligibility and reverberation time, can be estimated.
The application of auralization technologies is still being refined and is largely still in a beta stage; only two schools in the U.S. with acoustical academic programs, Penn State and Renssalaer, offer intensive teaching of the techniques. But its use will almost certainly proliferate because of its economic impact: Accurate prediction of a space’s acoustics means that materials and construction costs can also be more precisely forecast.
Another industry trend to watch is the proliferation of a much wider array of ready-made acoustical materials and components. Companies such as Auralex (www.auralex.com) have begun to market their products, which are migrating from the music recording and post-production sectors to architectural applications. Premade absorption and diffusion panels contain a modular design that allows them to be scaled to virtually any sized project. BASWAphon (www.baswa.com, www.artisansound.com) and Fellert’s Alpha Plaster (www.fellertusa.com) can be troweled onto surfaces of any shape and used to perform a combination of aesthetic, architectural, and acoustical functions.
RPG (www.rpginc.com) is another company that is migrating its product developments to architectural applications. The Clearsorber is a 5-mm-thick transparent panel with 0.5 mm perforations spaced 5 mm apart, creating an air boundary layer that provides absorption as air passes through the small holes. This inherent damping eliminates the need for fiberglass or other porous materials in the air cavity between the Clearsorber and the reflective surface behind it. The bottom line is that architects can now achieve acoustical effects without being limited to opaque materials.
“What I’m seeing is this explosion in the variety and availability of what I call ‘optimized surfaces,’” observes John Storyk, an architect and acoustician based in upstate New York who specializes in media technology facilities. “The vocabulary of components is getting bigger; where there was once three companies making soundproof doors, now there’s 15. The architect isn’t limited by materials choices anymore. You specify the shape and performance you want and there’s a product on the market that can achieve it for you.”
Other audio technology companies are moving from noncommercial sectors to industrial applications, especially in areas of systems control and routing. Sonance and others are pushing the envelope of what a transducer (speaker) can be, literally turning walls and windows into speakers. Distribution of the audio signal is further becoming more integrated not only into the physical structure but into building management systems (BMS) and commingled with Internet-based control, such as distribution solutions from Matrix Audio (www.matrixaudiodesigns.com) that manage energy flow as well as signal.
Not a Wireless World Yet
Expect to be dealing with wire for audio for the foreseeable future. It may be a wireless world in other ways, but Wi-Fi and other intangible signal transfer formats still have shortcomings in terms of bandwidth availability and security. That said, by-products of the Internet revolution include IP-based control of audio stored in the form of MP3 files on flash drives that are both easily interchangeable and that take up considerably less space. All this will lead to the diffusion of central control of audio, says Johnson Knowles, a consultant at Russ Berger Design Group in Dallas (www.rbdg.com), which specializes in high-tech corporate installations such as boardrooms and broadcasting facilities. “What’s happening is that more of the [audio] is passing through computers, and more of it can be locally controlled,” he says. “For the architect, it means that the notion of central control can be rethought for applications like restaurants, retail, even performance spaces. The audio can be tailored to the part of the space and to the moment or the event. Lots of flexibility, but it also means more architectural attention to wire management - where you put it, how it can be accessed and maintained and upgraded over time.”
Two other key audio technology areas that are continually undergoing evolution are digital signal processing (DSP) and PA systems. Regarding the former, the trend has been for large racks filled with analog equipment to be replaced with PCs running software-based DSP, the shorthand for which is “plug-ins.” The real benefit here, aside from space savings, is that upgrades to the audio systems won’t require wiring or conduit changes.
As for PA systems, the bulky cube is out, replaced by the more svelte line array system, which Swiss systems designer Dirk Noy calls “one of the most significant paradigm changes in recent audio history.” Citing the high degree of control offered by the array’s line source concept (as opposed to the more conventional point-source approach), Noy describes them as both a technological and an aesthetic solution for architects in planning performance spaces. “The line source approach avoids exciting a space’s reverberant surfaces and a lot of vertical dispersion in a system that is often less than 8 inches wide and easy to blend into the architectural design,” he says. Advances on this platform are constant and they are offered by most major providers, including JBL (Vertec), Meyer (Milo), and L-Acoustics (V-DOSC).
From an audio perspective, the role of the architect will continue its evolution into that of a systems integrator and manager, acting as the pivot point between design of the space and the technology that enables that space. As sound gets better - more precisely, as the expectation for better sound becomes more pervasive - architects will have to address audio on the nuance level. Where video demands line of sight, sound is an ambient creature, bringing acoustical issues increasingly to the forefront. Fortunately, the solutions are just as close.