Wilson Audio Specialties Alexia loudspeaker

With the help of 20:20 hindsight, it looks as if I made a decision when I joined Stereophile: to review a loudspeaker from Wilson Audio Specialties every 11 years. In June 1991, I reported on Wilson's WATT 3/Puppy 2 combination, which cost $12,740/pair in an automotive gloss-paint finish. This was followed in July 2002 by my review of the Wilson Sophia ($11,700/pair). And now, in December 2013, I am writing about the Wilson Alexia, which costs a not-inconsiderable $48,500/pair.

I first heard the Alexia at the 2012 Rocky Mountain Audio Fest, but didn't decide that I needed to get a pair into my listening room until the following January, when, at the 2013 Consumer Electronics Show, I heard a pair of them driven by Dan D'Agostino amplifiers and a dCS Vivaldi digital source, hooked up with Transparent cables. As I wrote in my online report from CES 2013, when I heard the hi-rez master file of Cantus singing Eric Whitacre's Lux Aurumque, "not only was the relationship between the sounds of the singers and musicians and the surrounding ambience of the recording venue breathtakingly real, so was the relationship between the musicians and the music. I have played Lux Aurumque on dozens of systems—never have I heard it sound so real, so musically involving." (footnote 1)

The Alexia
The floorstanding Alexia bears a strong family resemblance to the two earlier Wilson speakers I reviewed. Its truncated pyramidal profile resembles the Sophia's, while, like the WATT/Puppy, it comprises separate enclosures: the lower, rectangular one holds the two woofers, and the upper, pyramidal one the midrange unit and tweeter on its sloped-back front. And the Alexia is finished in high-gloss automotive paint.

There the resemblance ends. The Alexia is larger than either of the earlier speakers. The latest (and best-sounding) iteration of the WATT/Puppy, the W/P Sasha, reviewed by Art Dudley in July 2010, stands 44" high and weighs 197 lbs. At almost 54" tall, the Alexia is a head taller than the Sasha and weighs a backbreaking 256 lbs. But the newer speaker wears its bulk well, and its footprint in the listening room is not significantly greater than those of the smaller speakers.

The more significant difference concerns the drive-units. Like Wilson's various MAXX and Alexandria models, the Alexia's two woofers are of different sizes. An 8" woofer is mounted above a 10", both loaded with a large, 3"-diameter, aluminum-lined port on the cabinet rear. The idea behind using two woofers of different sizes is that the radiation pattern of the smaller one at the top of its passband better matches that of the midrange unit at the bottom of its passband. Whereas the XLF's woofer cones are made of Focal's proprietary W sandwich material and the Sasha's twin 8" cones are of polymer, the Alexia's bass drivers have paper cones.

The Alexia's 7" midrange driver, mounted in its own enclosure, is the same as that used in the XLF; it features a composite pulp/carbon-fiber cone, with a substantial half-roll rubber surround to confer greater dynamic range at the bottom of its passband. The midrange unit is resistively loaded by two foam-lined vertical slots on the rear panel, and the enclosure can be moved back and forth and have its tilt adjusted with spikes of various size that couple its rear to a stepped metal plate on the top of the woofer module. The Alexia's tweeter is a variation of the sophisticated silk-dome model Wilson used in the Alexandria XLF. This, too, is mounted in its own enclosure, which engages with both the top of the midrange enclosure and the underside of the black-anodized aluminum "bridge" that covers the module via spikes that sit in grooves machined into metal plates. The tweeter module can also be moved forward and back, and tilted, with respect to the midrange enclosure on which it sits. Wilson calls this ability to fine-tune the upper-frequency drivers Aspherical Group Delay; I refer you to Michael Fremer's explanation.

Electrical connection is via a single pair of brass binding posts mounted the rear of the woofer enclosure and standing proud of the cabinet. Two pairs of heavy-gauge cables emerge from the top of the woofer enclosure, and connect to two pairs of binding posts on the rear of the midrange enclosure: one pair each for the midrange and tweeter. All four of the Alexia's drive-units are connected with series power resistors in their feeds from the crossover, which is inside the woofer enclosure. The resistors for the upper-frequency units are accessible behind a metal plate on the top rear of the woofer enclosure. These are mounted on a heatsink and held in place by Allen-head bolts. Replacement is easy, and different values can be substituted to adjust the levels of the tweeter and midrange. Barrel resistors adjust the woofer level and damping; these are not intended to be changed by the buyer.

In common with the W/P Sasha and Alexandria XLF, the Alexia's enclosures are far removed from the usual rectangular monkey coffin. A subtle wave motif is machined into the woofer enclosure's side panels, and a pair of vertical walls flank the midrange module. The midrange enclosure is fundamentally a truncated pyramid, but with shoulders machined into the side panels and enclosing sidewalls rising either side of the small tweeter module, to support the metal bridge mentioned above. The walls of the woofer enclosure are built entirely of Wilson's proprietary X-Material, a mineral-loaded phenolic compound that is both extremely stiff and difficult to machine. Laser interferometry was used to optimize wall thickness and the placement of internal braces. Cloth-over-frame grilles are provided for each of the three modules; these have pins that plug into matching sockets in the front baffles.

The Alexia was designed by Dave Wilson and Vern Credille, Wilson's lead acoustic and electrical engineer. It is gorgeous to look at, but what matters most to audiophiles is how it sounds.

Setup
Wilson Audio is known for its attention to detail, even when that detail might seem unnecessary. For example, the manual states, "Place the ODD numbered modules in the LEFT channel section and the EVEN in the RIGHT channel position." Even the packaging is superbly thought out, and complete sets of tools and accessories are provided. Perhaps as should be expected at this price level, Wilson works hard to maximize the purchaser's pride of ownership. The head units are both contained in one crate; each woofer cabinet rolls out of its individual crate on sturdy wheels, which allow the speakers' positions in the room to be easily fine-tuned despite their size and weight.

When you buy a pair of Wilson Audio Specialties loudspeakers, the retailer will install them in your home and perform that fine-tuning. In my case, Wilson's Peter McGrath did the deed. Having adjusted the position and tilt of the tweeter and midrange modules for the height of my ears in my listening chair and their distance from the speakers—the exact settings are detailed in the manual's "Propagation Delay Correction" table—he rolled each speaker back and forth, and from side to side, until he was confident that they were close to their optimal positions. McGrath then placed two strips of masking tape at 90° to one another, each marked with a ½"-spaced grid. Listening carefully to each speaker in turn, he moved the enclosure in ½" steps in both planes and adjusted the toe-in until each Alexia sounded its best. (The grilles were left off.) He then replaced the wheels with the spiked feet and declared himself satisfied.

McGrath had fine-tuned this setup using a single track: "So Do I," from singer-songwriter Christy Moore's This Is the Day (CD, Sony 5032552). I asked him what was so helpful about this recording. "This track features two acoustic guitars, double bass, and voice. There's a little bit of reverb on the voice, enough elements to make it sufficiently complex, but not overwhelmingly so," he explained. "The voice has been recorded without microphone proximity effect, so if you hear what sounds like proximity effect, it's actually due to a room mode."

Listening
When Peter McGrath left, I began my own listening. Pink noise sounded smooth and uncolored when I was sitting in my chair on the exact listening axis set by McGrath, using the position adjustments for the tweeter and midrange modules and the precise amount of toe-in he'd settled on. However, if I moved slightly above or below that position, a narrow band of brightness became apparent.

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Footnote 1: You can listen to an excerpt of this work, albeit at 320kbps, 16-bit/44.1kHz MP3 quality, at the bottom of this page.
Source : stereophile[dot]com