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go to: Contents | Features | Bookshelf, Stand-Mount and Desktop | Floorstanding | Editors' Choice Awards EQUIPMENT REVIEW - KEF Blade This soundstage is also largely unaffected by frequency. Many speakers can convincingly place high-pitched instruments, like triangles, at the back of the stage; yet when it comes to low frequencies, their perspective flattens. In contrast, the Blade’s uniform dispersion allows all frequencies to partake of spatial feats. And so, when these speakers launch into the ever-useful Dvorák Serenades from Bohemia [Praga], the string bass, which often appears to be in the same plane as the other instruments, is properly behind them. As liberating as this soundstage stability is, it is even more gratifying to know that when I change listening locations the sound’s timbral balance and dynamics will also remain unchanged. Most of us have become so accustomed (and resigned) to timbral and dynamic shifts as we change positions that it is quite a revelation when the phenomenon is absent. With the Blades, you can not only shimmy along the sofa, you can stand up or walk around the room—in my home I could even venture into the next room—and the music still sounds the way it is supposed to. That means more musical enjoyment more of the time. Another thing I can be absolutely sure of when listening to the Blades is that notes will stop and start when they are supposed to. Folks, this is big. The ability to start, stop, and decay notes accurately is a rare quality, yet one that is fundamental to realistic sound reproduction. Pulling it off is an attribute of only the finest speakers, since it calls for tremendous driver and cabinet control. The Blades do this as well as any speaker I have heard. A good example of how note timing affects music occurs on the second track of the aforementioned Dvorák disc. This particular serenade is underpinned by a series of repeated piano chords. They are not quite staccato, more marcato. Through the Blades, the chords start right on time, so the pace is unerring. They also stop when they’re supposed to, which allows for a brief respite between them. Yet even as the pianist lifts his fingers from the keyboard, the hall reverb triggered by each chord decays ever so naturally into the ether. This is the way real music in a real space behaves. The low distortion responsible for the Blade’s accurate note timing pays two other huge dividends: resolution and low listener fatigue. These qualities may not be directly related to point-source design, but they are nonetheless important and unfailing. With the Blades, I enter every listening session knowing it can last as long as I like without my ears getting tired. And once the music begins, I am equally confident that I will be hearing things I never heard before, even with extremely familiar material. For instance, when I spin “Here Comes the Sun” from the Beatles’ remastered Abbey Road CD, I can discern with newfound clarity exactly how the group tweaked the synthesizer programming for each verse of “Sun, sun, sun, here we come.” And I can hear this without the slightest strain; it’s just there. As I’ve already mentioned, bass is another area where the Blades dole out previously unheard information. In this case, though, the revelations are not due to resolution but rather, once again, to that smooth power response. The uniform dispersion of frequencies is why, for example, I heard new bass information in Dexter even though my reference speakers have excellent bass extension. The Blades simply have a unique way of putting low frequencies into the room. Further, the Blade’s lows never overshadow the rest of the sonic spectrum. My standard tests for this are the guitar and vocals on the Nils Lofgren Acoustic Live CD. Both should sound rich and sweet. But beware: If the bass is even slightly overbearing the guitar veers into plumpness and Nils’ voice becomes chesty. The Blades do not fall into either trap. Imaging, tonal balance, and detail resolution are all admirable qualities, but I find that dynamics can affect musical enjoyment more than any of them. Here, as elsewhere, the Blades do not disappoint. Just listen to the gentle ocean-like swells at the opening of the second movement of Vaughan Williams’ Sea Symphony [Telarc]. The Blades beautifully track these subtle dynamic undulations. Yet the speaker can be dramatic, too, as when Nils Lofgren thumps his guitar body on “Blue Skies.” With the Blades, the impact is immediate—thanks to the same start/stop transient precision that serves note timing so well—and as powerful as a punch to the gut. To this point I have taken an analytical approach to the Blade’s performance, pointing out how well they perform in specific sonic categories. However, I would be remiss not to indicate that the speakers also create a cohesive whole that captures each recording’s distinct “gestalt.” This leads to another thing that I can be sure of when listening to the Blades: Whatever I play will sound like nothing else in my collection. Is there anything consistent about the Blade’s performance that is not positive Yes, there is one. For all the bass the Blades put out, how well they deliver that bass to the room, their transient response in the low end, and how deep they go without the slightest hint of stress, bass is the one segment of the musical range that could be better. Specifically, I wish for better pitch definition in the deepest bass. Entrances are not fuzzy, but the pitches lack authority. As a result, while it is easy to hear the Blade’s bass, it is less of a cinch to follow the notes of a bass line. Alas, no speaker is perfect; but the fact that this is my only significant caveat to the Blade’s overall excellence is a statement in itself. Put all these sonic attributes together and how does it sound In a word: glorious. The Blades are captivating, surprising, soothing, and refreshing. It is impossible not to eagerly anticipate spending time with them. They reveal but never showboat. Their rhythms sweep you along, their dynamics can move or stun you, their resolution informs you, their timbres enrich you, and their clarity makes delineating musical lines child’s play. Truly, with the Blades, taking in the entirety of the musical experience is effortless. From a practical standpoint you should know that driving the Blades is not as undemanding as listening to them. Their sensitivity is a modest 90dB. Without adequate oomph behind them, dynamics will not snap or swell—and that saps music of a lot of its emotional power. Indeed, at one point I was listening to the Blades marveling at how riveting the sound was and yet how utterly cold the music was leaving me. So, out went the 175Wpc Goldmund stereo amp, and in went the 350W Goldmund monoblocks. And just like that, the emotional connection awoke as if from a deep sleep. No review of a $30,000 speaker would be complete without a few words about the price. Thirty grand is unquestionably a lot of money for a pair of speakers. Yet I am constantly amazed by the rash of releases at or above this price point. (If you’ve ever seen Jonathan Valin breathlessly running around CES trying to cover them all, you 100 Guide to High-Performance Loudspeakers www.theabsolutesound.com previous page NEXT page
go to: Contents | Features | Bookshelf, Stand-Mount and Desktop | Floorstanding | Editors' Choice Awards EQUIPMENT REVIEW - KEF Blade know what I mean.) Indeed, other state-of-theart speakers from Wilson, Magico, YG, mbl, etc., tend to be dearer than the Blades. And yet I would unhesitatingly put the Blades in their league. I won’t call them a bargain—that would be the Maggie 3.7s—but I will say they deliver high value within their class. A speaker decision in this price range is bound to take into account many factors. In the case of the Blades, aesthetics are apt to be one of them. Their visual design was driven by their ambitious sonic goals (see “Behind the Blade’s Unique Façade”) and by KEF’s desire to make a modern industrial design statement. The result is one of industry’s most unusual shapes. In my home the big speaker evoked a variety of reactions. Some observers found the Blades “weird” looking, while others were intrigued. My kids immediately dubbed them the “fisheyes.” Perhaps tellingly, the most enthusiastic response came from a professional interior designer friend of mine, who dubbed them “awesome.” The fact that they can be customordered in sixteen colors sent her right over the edge. Personally, I have grown to appreciate the Blade’s form. Having lived with them for several months, I find that traditional box speakers now strike my eye as dull and dated. Apparently I am not alone. KEF reports significant early interest in the product based solely on its looks. Perhaps the well-heeled Significant Others of the world, who generally abhor big box speakers, will take a shine to the Blades and advocate their purchase. If that happens to you, knowing what you now know about their sound, for heaven’s sake consent. KEF’s Blade is a statement speaker in so many ways: as an aesthetic object; as a culmination of knowledge and experience gained over fifty years; as a demonstration that advanced technology can solve certain problems that brute force and exotic materials cannot; as the fulfillment of a theoretical ideal—and proof that the predicted benefits are real; and as the fruition of five years of work that not only met but exceeded all of its design goals. Above all, the Blade is a speaker that delivers an inordinate quantity of sonic and musical delight— no matter what you’re listening to. Behind the Blade’s Unique Façade The heart of the Blade’s design is the company’s familiar Uni-Q driver, in which the tweeter is located at the center of the midrange cone. Unlike old-fashioned coaxial drivers, this coincident driver arrangement avoids interference between each driver’s sonic spheres. Placing the tweeter right at the apex of the midrange cone unifies the two dispersion patterns. Another advantage of the Uni-Q is that its two component drivers are inherently time-aligned. Although the concept of concentric drivers—and, indeed, the Uni-Q itself—is decades old, KEF has continually refined it to more closely match the two drivers’ dispersion patterns. As always, the midrange cone acts as a “waveguide” for the tweeter’s lower frequencies, but in the Blade that cone is made from aluminum backed by a liquid crystal polymer skeleton. The extra rigidity conferred by those skeletal ribs not only makes for a better midrange driver, it improves tweeter performance. Meanwhile, a redesigned tweeter-dome shape, capped by the new “tangerine” waveguide, tames tweeter dispersion at the uppermost frequencies, while also providing poke protection. But how does bass get integrated into this carefully constructed mid/high point-source pattern The answer lies in the Blade’s use of four 9" woofers, two on each side of the cabinet. KEF chose side drivers for a multitude of reasons. First, physically connecting opposing woofers back-to-back cancels the cabinet vibrations a single woofer would induce. Second, the arrangement allows for a narrow front baffle, which minimizes diffraction. Third, having two stacked woofers per side widens dispersion at the top of their range, allowing the bass dispersion pattern to better blend with that of the midrange. Fourth, the woofer placement moves their center point well away from floor, avoiding that early reflection. Most importantly, though, the configuration allows the four bass drivers to be as close as possible to each other—and to the Uni-Q. This proximity to and symmetry around the Uni-Q is the key to the Blade’s full-range point-source capability. The arrangement positions the woofer cluster’s acoustic center such that it aligns precisely with that of the Uni-Q. The front baffle’s curved surface then serves as a final waveguide for the entire ensemble. Of course, the front baffle is not the only curved surface on the Blade. The entire cabinet (minus the base plate) consists of just two large curved pieces; one comprises the sides and front, the other forms the top and rear. KEF wanted a bold shape for its flagship for aesthetic reasons, but the curved cabinet also enhances rigidity, thereby reducing vibrations. Rigidity is further increased by extensive, computer-optimized internal bracing. Finally, the enclosure is made of glass-reinforced composite fiber, which is similar in strength to carbon fiber, though not as light (as I can personally attest). AT 101 Guide to High-Performance Loudspeakers www.theabsolutesound.com previous page NEXT page
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