Aerial Acoustics Model 20T loudspeaker

Loudspeaker design is an art and a science. Anyone who tells you it's only one or the other is probably building or listening to some awful-sounding speakers. Design a speaker in an anechoic chamber for the "theoretical" world, and there's no guarantee it will sound good in the real one. Even building a speaker that excels at "real-room" measurements doesn't guarantee that it will sound all that convincing when reproducing music. We can't measure everything, and what we can measure can't be reliably ranked in terms of what's important to most listeners.

Do we really want to listen to "accurate" loudspeakers if the vast majority of recordings were mixed and mastered on "inaccurate" ones? Most microphones have more peaks than the Rocky Mountains. Do we really want to hear recordings made using such mikes reproduced "accurately"?

How's the response in your room? Flat? Probably not. Most rooms have bumps and suckouts that can turn the most "accurate" loudspeaker into a lumpy mattress of sound.

Looking at the range of measurements made by John Atkinson in the aftermath of any "observational" Stereophile loudspeaker review, there will hopefully be some correlation between what was heard and what was measured. But in the end, a reviewer's—and a consumer's—subjective reaction will be based on a complex set of factors that includes the room, the setup, musical taste, and which performance factors loom largest on his or her listening horizon.

Often, the ear can be fooled into hearing a rise in one area when in fact there's a dip someplace else. In the end, does it matter which it is when, ultimately, one's reaction to a design is based on a complex mix of ingredients and proportions that's often impossible to sort out?

Designing purely by subjective "taste" can sometimes yield surprisingly good results, but I wouldn't bet on such a designer establishing an enviable track record. Every speaker design—even the best and most expensive—is an assemblage of compromises based on what's known and what's not, what's possible and what's not, what technologies are available, and, in the end, the personal tastes and philosophies of the designer.

That this is an inexact science married to an inelegant art form is proven at every Consumer Electronics Show. I spent a whirlwind day in Las Vegas last January year traveling from room to room with record producer Rick Rubin and Stereophile's Rick Rosen, and although all of the rooms we liked sounded very different from one another, and we didn't always agree on whether we liked what we heard enough to want to own it, there were mostly unanimous thumbs up or down almost every time.

One of the rooms we visited was the Aerial Acoustics-Musical Fidelity suite, atop the Mirage Hotel. The heart of the system was what I'd just been listening to at home: Aerial's Model 20Ts driven by a Musical Fidelity kWP preamp and kW monoblocks. Different room, different results, but close enough to sound familiar, most of the difference being in the bass. The big Mirage room proved to be an ideal venue for the 20Ts, my room somewhat less so; but I know my room well, so I wasn't at all surprised by what I heard that day.

Heavy lifting
With 12 years' experience at a/d/s/ designing individual drivers and complete loudspeakers before starting his own company, Aerial's Michael Kelly is an industry veteran. When he left a/d/s/ in 1986 to go back to college, Kelly was the firm's executive vice president in charge of research and development. In 1991, armed with an MBA, he founded Aerial Acoustics and introduced his Model 10T. While not the most original-looking speaker—it was clearly modeled after KEF's groundbreaking 105 and B&W's 801—the 10T offered outstanding full-range performance, measured and otherwise, at a relatively low price of $7000/pair.

The 10T was big and weighed 280 lbs because Kelly felt that there was no substitute for a well-braced, resonance-free bass cabinet whose output could extend down to 20Hz, -6dB. He still feels that way: the new Model 20T weighs 270 lbs, which includes an 80-lb head unit, a 170-lb bass cabinet, and a 20-lb adjustable base of laser-cut steel with outboard spikes. The 20T is smaller and far better proportioned than was the 10T, and is therefore more attractive and far easier to integrate into a living room.

Clearly, the 20T's takeoff point was Wilson Audio Specialties' highly successful WATT/Puppy series: small speakers that can deliver big sound. (After my review of the WATT/Puppy 7 was published in the September 2003 Stereophile, a representative from the resurrected Fried Products pointed out to me that Bud Fried had built a WATT-shaped midrange-tweeter head array long before Wilson—or anyone else, for that matter.)

The 20T's upper and lower cabinets are built to Aerial's specifications by the Hornslet Cabinet factory in Denmark, which also builds enclosures to spec for Audio Physic, Linn, DALI, Naim, and many other well-known loudspeaker companies. Using its patented Hornflex technology, Hornslet can build ultra-complex cabinets, including ones with curvaceous surfaces. While the Hornflex wasn't used to build the 20T, during a visit I paid to the factory last fall I was shown the geometrically complex CAD drawing of the 20T that Aerial had given Hornslet, their job to turn it into a manufacturable product. The drawing was impressive; the 20T looked impossibly complex and fanatically well-braced.

The bass cabinet's two-in-one construction consists of inner and outer enclosures of 1"-thick MDF with a constrained damping layer in between. Extensive three-dimensional bracing permeates the cabinet interior, the braces penetrating the damping material and causing the inner enclosure to push against the outer one. The bass cabinet, measuring 30" H by 13" W by 22" D, weighs 170 lbs and is claimed to be extremely rigid, stiffly braced, effectively damped. Rap it with your knuckles and you'll come away bruised. While I wouldn't expect the kind of virtually resonant-free cabinet measurement Rockport Technologies' Antares delivered—see my review in August 2002—I imagine something pretty close.

The upper, 80-lb cabinet is built using the same complex construction, but has a 2"-thick wall of MDF behind the midrange driver that creates an isolated, double-vented rear chamber containing the mid/HF crossover network. Both cabinets are complex geometric shapes, but unless they're brought to your attention, you might not appreciate the difficulties involved in their construction—especially the intersection of a complex seam in the bass cabinet's sidewalls. Also note how the mirror-imaged wood veneers line up properly at the seams on the front baffle, and in their flow from head unit to bass cabinet. If you can inspect a 20T in person, a close look at such intricacies can be fascinating.

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