Wilson Audio Specialties Alexx Loudspeaker

Passing the Torch

Equipment report
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Wilson Audio Alexx
Wilson Audio Specialties Alexx Loudspeaker

The enclosure also benefits from development work on the WAMM; the Alexx's cabinet supporting the upper-midrange module features one section of "W-Material," which was developed specifically for the WAMM. This is a phenolic resin in which thin sheets of a titanium-aluminum alloy are embedded in the resin an eighth of an inch apart. The WAMM makes extensive use of this exotic material; in the Alexx it appears in the adjustment track-bed for the upper-midrange driver. This plate of W-Material is painted silver no matter what color cabinet you choose (it’s only visible from the back). The majority of the enclosures, including the woofer cabinet and the supporting structure for the midrange and tweeter enclosures, are made from the third-generation of Wilson’s X-Material. A third material, “S-Material,” is used in the midrange baffles. Wilson has found that the different densities and stiffnesses of the various materials perform best in specific locations. All the materials are extremely solid and heavy, and all combine stiffness with damping properties. Incidentally, these materials are very time-consuming to machine because of their density; the cutting bits must move very slowly, and be replaced frequently. 

The Alexx’s two midrange and single tweeter enclosures can be adjusted in two axes to realize perfect time alignment at the listening position—a technology Wilson calls Aspherical Propagation Delay. That is, the outputs from each of the drive units combine into a coherent waveform, arriving together at the listener’s ears. A very precisely engineered and executed mechanism, mostly made from machined aluminum parts, realizes this adjustment. Each of the three upper drivers can be moved back and forth, as well as rotated. The back-and-forth movement adjusts the driver’s arrival time at the listening seat relative to the other drivers. The rotation optimizes each driver’s dispersion for a particular listening distance and listening height. A detailed chart in the owner’s manual precisely defines each of the settings for your installation. The time-alignment resolution in the Alexx is about 15 microseconds; in the WAMM it is 5 microseconds. Much of the WAMM’s cost is in the extremely fine mechanisms required to realize this precision.

Wilson believes very strongly that time alignment is critical to fidelity. In fact, the original WAMM from 1981 was built around this concept. It required that David Wilson himself set up every pair of WAMMs to dial-in the time alignment. Wilson has long since developed the designs and techniques I’ve just described so that anyone can calibrate the speaker using Wilson’s charts. 

Looking at the Alexx, it’s apparent that a lot of engineering effort and expense went into the separate midrange and tweeter enclosures along with the mechanisms for adjusting their time alignment. If time alignment is so important, why is Wilson the only loudspeaker company pursuing this path? One explanation is that the challenge of designing and building such structures and mechanisms, on a production basis, is simply too daunting. It’s not just the mechanisms themselves that are challenging, so is coupling a movable enclosure to another enclosure without compromising the system’s structural rigidity and resistance to vibration. When you look closely at the design and parts needed to realize movable sub-enclosures with such precision, you realize that time alignment is much easier said than done.

After Wilson Audio’s John Giolas and Peter McGrath finished setting up and calibrating the Alexx in my room and we’d listened for about two hours, they intentionally misaligned the tweeter by moving it back about a millimeter so that I could hear what happens when the tweeter’s output isn’t perfectly coincident with the output from the midrange drivers. The change was immediately obvious; with the tweeter correctly aligned the midrange and treble sounded more correct (realistic) in timbre, and the sound had a greater focus and coherence through the midband.

Finally, I must comment on the owner’s manual. The Alexx manual is a model of clarity, comprehensiveness, writing/photographic quality, and beautiful printing on super-premium paper. It pains me to see shoddy owner’s manuals for expensive products. They reflect badly on the products and on the industry as a whole. The customer is paying for a premium component, and every aspect of the presentation should be commensurate with the work that went into that component. 

It almost goes without saying after all these years that the Alexx’s execution, fit ’n’ finish, and build-quality are simply impeccable. This is as good as it gets, with the stunning paintwork and the meticulous way all the parts fit together. While on a tour of the Wilson factory a few years ago I happened to see a cabinet that had been rejected for a paint imperfection. I looked closely but couldn’t see the flaw. It was pointed out to me, and I still couldn’t see it. After a few minutes I finally noticed a barely perceptible ripple in the painted surface—and it was on the bottom of the cabinet! David Wilson once explained to me that any deviation from the standard of perfection dilutes the culture and would ultimately compromise the brand. That’s the same reason you don’t see a budget line of Wilson speakers with relaxed build and finish standards—cutting corners here and there can be a slippery slope. Every product, from TuneTot to WAMM, is built to the same standard.

Sound
While I was working on this review the next-generation Corvette was unveiled to great fanfare. This new ’Vette is strikingly different in styling and design from previous models over the car’s 66-year history. For starters, the new model is based on a mid-engine platform, an architecture previously found only in six-figure supercars. By necessity, the new model looks very different from its predecessors. An automotive journalist wrote about the styling: “The overall effect is one that instantly says both ‘Corvette!’ and ‘This is something different.’”

That observation of how the new Corvette looks mirrored my view of how the Alexx sounds; the speaker embodies the classic Wilson attributes yet immediately establishes itself as something new and different. It’s clearly a Wilson, but an evolved Wilson. 

One of those classic Wilson qualities is bottom-end weight, dynamic impact, and solidity—anchoring the music with a powerful foundation. In this regard, the Alexx is characteristic Wilson, with a strong “bottom-up” presentation. But the Alexx takes these previous Wilson hallmarks to a new level of performance, with more sudden dynamic impact and faster decay, resulting in a tighter sound with greater low-frequency pitch definition and resolution. The speaker is also more dynamically agile and “light on its feet” than previous Wilsons. The Alexx deftly combines weight and authority with speed and precision, resulting in a very satisfying bottom end. This muscular and powerful bass is as adept at portraying the body, size, and power of an orchestra’s bass section as it is at accurately reproducing kick drum and electric bass. Stevie Ray Vaughan’s spectacular rendition of the Hendrix classic “Voodoo Chile” [Couldn’t Stand the Weather, Analogue Productions 45rpm vinyl] opens with just Stevie’s guitar and the kick drum, with the latter instrument reproduced by the Alexx with deep extension, effortless transient impact, and a resolution of detail that conveyed the impression of a drumhead being struck and the body of the drum resonating. When a drum is reproduced in a way that is much more detailed than just a low-frequency thump, the mind’s eye conjures up a more vivid impression of the drummer playing the kit.