Articles by Keith Yates

On Home Theatre design, acoustical theory and practice, and audio/video technologies. From Audio/Video Interiors, Custom Builder, Stereophile, Stereophile Guide to Home Theater, Archi-Tech, Audio, High Performance Review, PCWorld and others.

"In-Wall Speakers Test Part 1"--Audio/Video Interiors, February '96
Computer-based acoustical measurements were taken of 10 popular models of in-wall loudspeakers and graphed to provide useful information about the speakers' total acoustical behavior. Subjective listening tests were conducted to compare each in-wall speaker to conventional, freestanding speakers, including a professional control-room monitor. The resulting 10-page feature was the first to candidly evaluate in-wall loudspeakers against the standards set by "serious" high-fidelity devices. Tested models included top-of-the-line offerings from Atlas, Boston Acoustics, Energy, KEF, Klipsch, MTX, Niles, Parasound, Polk and Speakercraft.

"In-Wall Speakers Test Part 2"--Audio/Video Interiors, March '96
This 14-page second installment in the first-ever rigorous test of in-wall speakers included flagship offerings from 10 leading manufacturers, including a/d/s/, Apogee, Bohlender-Graebener, B&W, Canton, In-Wall Audio, MB Quart, McIntosh, Sonance and Triad. In addition to reporting the results of the objective and subjective testing, the test methodology itself was explored in detail, accompanied by an explanation of how to interpret the response graphs.

"In-Wall Speakers Test Part 3"--Audio/Video Interiors, '98
The third installment puts two actively biamplified in-wall models—B&W's top-of-the-line AWM70 and the Linn Sekrit—to the test, along with the Triad OmniPlus, M&K SW95 and Vandersteen VSM-1.

"Virtual Acoustics"--Audio/Video Interiors, April '95
"Auralization" is a new computer-based process by which public performance spaces—from stadiums and concert halls to places of worship—can be "auditioned" prior to their being constructed. Technology now emerging from research labs could conceivably bring this industrial-strength tool to the design and analysis of residential venues—home theaters, listening rooms and small concert/recital halls. The underlying technology is explored, and specific improvements are suggested for adapting this promising new tool to the design of high-quality music and film venues in the home.

"Halcyon"--Stereophile Guide to Home Theater, September '99
Uncut version of the structural decisions, acoustic treatment, equipment selections, etc. behind the Washington D.C. area home theater designed by Keith Yates Design Group and featured in SGHT.

"The Well-Tuned Room, Part 1"--Audio/Video Interiors, March '93
It's not the quality of the components, but rather the physical relationships between the loudspeakers, the listeners, and the acoustical environment that dictates sound quality in residential environments. The sonic effects of typical speaker-room mismatches are described. Basic acoustical concepts — reflection, absorption, diffusion, standing waves—are introduced. "Room boom" is seen to result from mathematically unfavorable room geometry. Common room features—carpeting, sofas, windows etc.—are seen to introduce acoustical changes, but offer limited opportunity to actively control sound. First installment of a comprehensive, ongoing feature series examining the role of acoustics in residential A/V systems.

"The Well-Tuned Room, Part 2"--Audio/Video Interiors, May '93
Making the most of a room's sonic potential begins in the design phase, when the geometry, dimensions and construction materials are as-yet unspecified. The importance of room ratios (height/width/length) is underscored, and some favorable ones ranked. The value of low background noise is stressed, and the concepts of transmission loss and STC ratings briefly described. Several common wall constructions are described and ranked by their efficiency as sound "excluders". Guidelines are provided to ensure that windows don't become the weak links in the room's defense against sound infiltration.

"The Well-Tuned Room, Part 3"--Audio/Video Interiors, January '94
"Reverberation time" is introduced. Absorption can be a particularly cost-effective means of controlling sound in residential settings, improving the intelligibility of speech and the clarity of music. Different classes of absorbers—frictional, flexural and resonant—are described. Physical requirements, including size and location, are discussed for the various absorber classes. Low frequency absorption or "bass trapping" is addressed, along with some commercially available devices. Historical use of resonant absorption, dating back to the ancient Greeks, is highlighted.

"The Well-Tuned Room, Part 4"--Audio/Video Interiors, May '94
Using diffusion to bring big-room sonic splendor to small rooms. Diffusion's role in fostering spatial envelopment or the "surround" effect. Hemidisk (one-dimensional) vs. hemispherical (two-dimensional) diffusors. Two popular brands of commercially available 1-D and 2-D diffusors. Bookcases as diffusors. Practical application notes and photos of an ambitious Keith Yates Private Concert Hall project.

"Transparency in Audio/Video Design"--Archi-Tech, Spring '99
A/V hardware is simultaneously proliferating and disappearing—concealed behind hidden panels, ensconced in separate control rooms, motorized out of view when not in use, etc. A new, transparent covering from a German lab promises to bring acoustic control to windows, something previously thought unachievable.

"Simple Acoustic Solutions"--Audio/Video Interiors, January '95
Some of the common sources of acoustic disappointment in home A/V rooms are discussed, along with straightforward advice as to how to deal with the problems and maximize the probability of acoustical success in the home theater. A cost-effective, step-by-step "before and after" room makeover is discussed and illustrated.

"Music and Audio Minimalism"--Stereophile, November '88
This cover story examines the future of high-end audio and concludes that the refusal to equalize, expand, compress or otherwise tamper with the original recording limits the opportunities to improve audio realism. Digital signal processing (DSP) is seen as opening new possibilities of tailoring sound to suit particular acoustical environments and listener preferences without contaminating the audio signal with noise, distortion, "veiling," or a flattening of the spatial dimension. Two-channel audiophile playback systems will give way to DSP-based multichannel surround-type systems because they're capable of more closely replicating the live experience in the home.

"A Matter of Diffusion"--Stereophile, April '88
The biggest obstacle to you-are-there sound quality is not power output, distortion, frequency response, signal-to-noise ratio or any other yardstick of equipment quality: It is the acoustical behavior of the listening room. A brand-new acoustical technology—the use of quadratic residue mathematics to design broad bandwidth diffusors—is introduced for the first time to the audiophile marketplace. A reference-quality soundroom is evaluated with and without diffusors, using a broad sampling of the world's most highly acclaimed loudspeakers. Subjective results are described speaker-by-speaker. It is concluded that the frontier of high fidelity is not some new miracle electronic component, but the from-the-ground-up A/V room.

"Behind the Scenes"--Custom Builder, September/October '92
Recently introduced components allow audio and video signals to be piped throughout a home with minimal noise and distortion. The difference between "distributed" and true "multizone" audio systems is described. Some of the more popular brands of keypad-type multizone systems—Soundstream, Audioaccess, Sony—are compared. Wiring requirements for these proprietary systems are outlined, and the need for planning and specialized design expertise stressed. The magazine's cover showcases a California family room remodel project by Keith Yates, with motorized cabinetry and range hood to allow for optimum viewing and listening conditions while the owners are in the adjoining kitchen.

"What's Wrong with this Picture?"--Audio/Video Interiors, July '92
Today's best television sets are deliberately misadjusted at the factory. The reason lies in the dynamic of the salesfloor, where TVs are sold on how their picture "pops" off a merchandise display wall full of competing sets. The analogy of adding blue dye to detergents to "brighten and whiten" clothes is used to describe the bluish cast to today's "brighter" TVs. The NTSC standard for color temperature (i.e., white point) is introduced, along with the reasons video production studios carefully calibrate their monitors to 6500° Kelvin. Suggestion is made to recalibrate consumer sets to proper NTSC standards—not the manufacturer's default settings—and what to look for in terms of improved picture quality.

"Are Audiophiles Music Lovers?"--Stereophile, November '91
The author conducted a costly experiment: Building an 8,000 square foot audiophile mecca with a 140-seat concert hall in the middle. An architectural, musical and acoustic success, there was only one problem: The audiophiles didn't show up—though their neighbors did.

"Hi-Fi Floppy"--PC World, April '85
The integration of the personal computer with the home entertainment system is inevitable. The basis of the union will be the digitization of music and the possibility of compressing/reducing it to more manageable file sizes. An overview of digital audio basics is provided, along with details of a prototype floppy disk-based digital audio recording and playback device, the CompuSonics DSP-1000, which, by relying on psychoacoustic mechanisms, can safely discard redundant and perceptually unretrievable information to reduce data rates by a factor of 10 . (This discussion predated by 6-7 years the actual introducution of the first "data reduction" consumer audio components—Sony's MD and Philips' DCC and, later, Dolby's AC-3.)

"ProActive Speakers"--Audio/Video Interiors, November '94
Active, or self-powered, loudspeakers enjoy many technical and sonic advantages over their conventional, passive, cousins. Products from two leading exponents of active speaker technology, Meridian and Genelec, are outlined. The chief impediment to greater penetration of actives into the high-quality consumer world is seen to come from manufacturers' marketing, not engineering, departments.

"A Theatrical Experience"--Custom Builder, March/April '93
The basic difference between a media room outfitted with "home theatre" equipment and a true Home Theatre is presented for custom home builders confused by the terminology and competing claims of manufacturers and installers. The fundamental goal of the true Home Theatre experience—the "willing suspension of disbelief"—is briefly described. Achieving it is seen to come from focusing more on the habitat than on the hardware.

"Whirring into the Future"--Audio/Video Interiors, October '92
Incorporating motorized features to enhance the listening/viewing experience. Examples of two custom-designed, motorized entertainment cabinets that successfully address the aural and optical relationships between audience and the playback/display system. Why motorization can prove even more useful in casual residential environments—family rooms, studies, bedrooms, etc.—than in dedicated A/V spaces like Home Theatres and listening rooms.

"Slipped Discs"--Sacramento, May '83
The soon-to-be-introduced Compact Disc player will offer unparalleled handling convenience, freedom from noise, and long playing times, but actual audio quality of pre-production samples is disappointing—gritty and fatiguing compared to the best analog systems. Despite initial disappointment, it is suggested that the technology can be improved "to the point where it can surpass the best analog devices" by increasing the sampling rate and bit resolution. (Over a decade later, nearly all CD players now includes these technical—and sonic—improvements.) The article was widely distributed throughout North America and the U.K., and is thought to be the first to state that the new technology had a long way to go before achieving the promised "perfect sound forever."

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