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Equipment Review
August 1999

Wilson Audio Grand SLAMM Series II Loudspeakers

by Jeff Fritz

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A classic evolves.


Review at a Glance
Sound Fast, extended, integrated and utterly uncolored sound -- be ready to hear what your system really sounds like; the Series II upgrade removes a small amount of grain in the extreme high frequencies and creates a "greater sense of musical continuity."
Features State-of-the-art drivers and cabinet materials, and a wealth of manufacturing expertise behind them; a speaker with seemingly no compromises.
Use Require proper placement and adjustment according to Wilson Audio’s standards to be aligned faithfully in the time domain and thus operating at their highest level.
Value Perhaps the best-known luxury item in high-end audio; a no-compromise speaker with a price to match that, so far as Jeff can discern, is without flaws.

In designing the X-1 Grand SLAMM Series II, David Wilson has taken a no-compromise approach to sound reproduction. What exactly, in real terms, does this mean? Audiophiles have long felt that faithfully passing the signal to the listener should be the designer’s goal. Anything that interferes with this is considered a compromise. With electronics, the proverbial straight-wire-with-gain approach has led to components that editorialize little, leaving the music fully intact. In fact, even moderately priced amplifiers and preamplifiers have achieved exceptional performance when compared to their ancestors.

Speakers are somewhat different. I’ve heard it stated many times that of all the components in the reproduction chain, speakers are the most personal. The diversity of speaker configurations is dizzying, as is the performance of the available models. With this in mind, it’s no wonder that speakers are discussed more than any other component. Arguably more so than electronics, speakers involve trade-offs. Manufacturers rarely attempt to build state-of-the-art speakers due to practical considerations such as size, manufacturability, and shipping cost -- not to mention the R&D effort and skill required to make such an exercise meaningful. Therefore we’re left with a product that greatly reflects the sonic priorities (or acceptable compromises) of the designer. When that designer’s vision parallels our own, we’re likely to find a speaker that communicates the musical message to us.

The Wilson X-1 Grand SLAMM Series II was conceived with many of the aforementioned shackles removed. Cost and size were taken out of the equation so that virtually only performance considerations remained. This was an assault on the state of the art without practical limitation. We examined the X-1’s design and materials in detail in the informational sneak peek, so we are left simply with the question of its sound. It’s fair to say that I entered into this review expecting no compromises in the Grand SLAMM’s performance because there were almost no trade-offs in its conception.


The X-1 was installed in my 18'L x 14'W x 9.5'H listening room according to the Wilson Audio setup procedure (see the Wilson website for details). The speakers were then fine-tuned by Matt Tucker of Wilson, who has set up his fair share of Grand SLAMMs. Room treatments included large acoustically absorbent panels on the side walls and behind the listening position. Bass traps were positioned behind the speakers in the room’s corners. Ancillary equipment included a Pioneer DVD player as the primary source, playing both CDs and audio-only DVDs. The preamplifier used was a Proceed Pre, although this was replaced with a Coda 04r towards the end of the review period. A Mark Levinson No.335 provided amplification, while Transparent Audio Super XL cabling tied everything together. A dedicated 30-amp AC line fed the power amplifier, and a similar 20-amp line powered everything else.


The performance of the X-1 Series II called into question many of my preconceptions about loudspeakers. Where other speakers have historically been weak, the X-1 excelled. These particular areas were most noticeable upon first audition because I simply wasn’t familiar with the level of performance the Grand SLAMMs represent. I will not bore you with a descriptive breakdown of high-, mid-, and low-frequency ranges because, as you would expect, each is excellent. This could easily sound like any other speaker review you’ve read, without bringing to light the qualities that make this speaker system unique. I will therefore concentrate on the differences between the X-1’s sound and that of any other speaker I’ve auditioned.

Speed in a speaker is noticed when, by comparison, another speaker is slow. The X-1 proved to sound blindingly fast immediately after referencing other systems with one or more problems in the areas of cabinet coloration, slow rise/settling times, and poor room interaction (among others). After listening to the SLAMMs for days on end, the sense of speed became more a natural representation of the music. It came to me that I’ve never heard a speaker that I would characterize as too fast (neither have I heard anyone else make this observation). The Grand SLAMM’s speed removed much of the perception that a mechanical object was reproducing the individual sounds.

The integration of the X-1’s drive units produced a coherence of sound that was seamless. The crossover points defied detection as the entire frequency range was reproduced with equal precision. Whatever the sound, whatever the frequency, it was just there. There were no audible anomalies in the music’s presentation. This made listening to complex passages thrilling because the weakness (or strength) of a particular range was never highlighted. The continuous soundscape that was presented showed no discontinuities. One sound just flowed into the next, much as with the words of a good writer.

Never was there a sense that the X-1 was adding to or subtracting from the music in any way. In this respect, its representation was as natural as I’ve heard. Audiophile terms such as warmth and bloom simply do not apply, but neither do dry, cool, or bright. The Grand SLAMM’s extension at either frequency extreme was neither tipped up nor bloated; rather, the inherent extension was simply present when the music called for it.

Typically, distortion artifacts become noticeable to me in the extreme treble and very low bass. The Grand SLAMMs never hinted at distortion in these areas. The treble had no grain or sizzle, but at the same time it was detailed. This characteristic did not change with volume level. Distortion brought on by driver compression and cabinet resonance, while reproducing low bass, was absent as well. It is my guess that the frequency response of the X-1 does not dramatically change with output level, at least not in musical terms. Listening to Stanley Clarke’s "We Supply" from The Bass-ic Collection [Epic EK 64277] gave an excellent example of the X-1’s ability to render bass notes with precision and accuracy. The tandem of 12" and 15" woofers destroyed the myth that large drivers sound subjectively slower than smaller ones. In fact, I have never heard bass reproduced with the agility and finesse that the X-1 is capable of. Again, the integration between the Focal woofers and the Dynaudio midranges must be at least partially responsible.

I learned quite a bit about the accurate portrayal of the soundstage while conducting this review. I’ve heard some suggest that the soundstage of the Grand SLAMMs seemed unnaturally large. I realized late in the review period, though, that most speakers vary the scale with which they produce certain images within the soundstage. Whether this is due to frequency anomalies or some form of compression, I can’t say. I do know that the X-1 produces images that are proportionately scaled to one another. This is especially noticeable in the midrange and midbass of the Grand SLAMM. Vocal tracks such as "Love Is Stronger Than Pride" from Sade’s The Best Of Sade [EK 66686] provide a good example of this phenomenon. Listen to this piece from about 3:50 to 4:15 while imagining the relationship between the background vocals and drums. Their interplay should be proportionately portrayed with full-scale images of each within the soundstage. I don’t know any other way to describe this trait other than by saying that it sounds real.

The Grand SLAMM Series II does adopt characteristics passed on by the electronics. In this respect, it is not a component whose sound you can "mix" with another to create a third, more preferable choice. For me, a component with a sound I was uncomfortable with became even more unsettling in the context of my system. By the same token, components that added little allowed the X-1 to communicate more freely with the listener. I would describe this trait as transparency, a purity of sound that demands excellence up the chain -- or, at the very least, that you like whatever characteristic sound your system has. You are certainly going to hear it.

In an attempt to give you a sonic snapshot of this remarkable speaker, I’m going to tell you what I didn’t hear. Hopefully this will answer more questions than it will raise. It seems fitting, though, in light of how little the X-1 adds to the music. Here goes. In no way was the X-1’s sound boxy, slow, boomy, or loose. I did not hear any brightness, grain, or dulling of the upper treble. The midrange was neither lean nor closed-in. And I did not detect any coloration (such as the cupped-hands syndrome) in vocals, male or female. No component is totally without a signature sound, but the X-1 Series II was as close as I’ve heard. "What then did you hear?" I can hear you ask. Well, that’s a good question. My answer would be "as neutral a speaker as I’ve heard." Do not confuse "neutral" in any way with "analytical." In fact, neutral can be defined as "musicality without interference."

The old versus the new

I lived with the original version of the X-1 for several months before the upgrade to Series II status was completed. The sound of the Series II was hardly a departure from that which I was accustomed. As the weeks passed, though, it became clear that there was a definite improvement. It did take me some time to get a handle on exactly what that improvement was. The extreme high frequencies possessed a delicate, unforced nature not present before. I don’t want to overemphasize this because it is subtle. Over the long term, it became an important refinement. It was as if the leading edge of upper-frequency transients lost a very small bit of grain. Although hard to describe in audiophile terms, this subtle reduction in distortion was most noticeable while listening to low-level acoustical music such as the Alison Krauss track "Oh Atlanta" (fiddle, mandolin, acoustic bass and guitar) from Now That I’ve Found You: A Collection [Rounder CD 0325]. I have to say that it was not easy to recognize the absence of this distortion at first, but over the long haul it was very important.

In listening to the new X-1, I also felt an even greater sense of musical continuity. The X-1 Series I could not be called lacking in this department, but after several weeks of listening to the new version, I began to marvel at my inability to critique specific frequency ranges. The evenness of sound coupled with its total detachment from the cabinets defied my attempt to compartmentalize the music to individual drivers. Although I have no proof, I would think that the refinement of the crossover is at work here. This made it quite difficult (and frustrating!) to enter into "reviewer mode." I just wanted to listen to the music.

So where does that leave us?

Someone, somewhere, once stated that until we reach the point where you simply can’t differentiate between live and reproduced music, the high-end will survive. In this respect, the state of the art remains a moving target. No perfect component exists, including the X-1 Grand SLAMM Series II. This leaves me with the realization that although this speaker is not without flaws, I haven’t really been able to put my finger on any of them. As a reviewer I simply must be able to assess a component’s strengths and weaknesses and then describe them to the reader. I’m afraid, though, that until I hear a speaker that betters the X-1 in a specific area, I simply cannot declare an area of its performance as weak. When I do hear it, I can proudly state, "There it is! I heard it, a problem!" I’m not at this point yet, but I almost wish I were. It would have made writing this review easier.

Wilson does make a more expensive speaker called the WAMM ($157,000 per four-piece system), which I’ve not heard. They also have in their product line a super subwoofer (XS) that is rated to extend deeper in the bass. And, of course, several other companies claim the state-of-the-art title for their own offerings. It is all quite debatable. Maybe over time, with many more live performances ingrained in my aural memory, I will be able to tell you in tangible terms why the sound doesn’t reach "live" status. Until then, the X-1 remains as faithful a bridge to the music as I’ve heard. As far as the question I left you with in the sneak peek: "Does the X-1 Grand SLAMM Series II live up to David Wilson’s original concept?" You’ll simply have to ask him. I can say that it works for me.

...Jeff Fritz

Wilson Audio X-1 Grand SLAMM Series II Loudspeakers
Price: $75,900 USD per pair; upgrade from Series I to Series II, $8400.
Warranty: Five years parts and labor.

Wilson Audio Specialties, Inc.
2333 Mountain Vista Lane
Provo, Utah 84606
Phone: (801) 377-2233
Fax: (801) 377-2282

E-mail: was@wilsonaudio.com
Website: www.wilsonaudio.com

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