To make this complex, highly-engineered “box” the perfect blend of stiffness, mass, and damping, Vassilkov experimented with many materials, eventually settling on a crushed-marble-and-acrylic-based composite that can be turned into a slurry, poured into a (very expensive) mold, cast in the form of an artfully sculpted loudspeaker enclosure (with extensive internal stiffening spars to break up resonance nodes and standing waves), allowed to age, and then hand-coated on the inside with layers of dampening materials and on the outside with layers of lacquer. Also on the inside, separate constrained-layer carbon-fiber chambers with non-parallel sidewalls provide ideal environments for the midrange and tweeter drivers.
Speaking of drivers, Vassilkov is perfectly aware of the “downsides” of ceramic cones, but believes that their upsides (at least in their latest versions—Accuton has greatly improved its ceramic cones and magnetic motors) outweigh their demerits, because of their high linearity throughout their passbands. By using only the latest and best Accuton cones—and very select and exceptionally closely matched pairs of each (Vassilkov goes through hundreds of these drivers and keeps only the scant few that meet his tolerances and standards)—putting them in an enclosure scientifically designed not to exacerbate their problems by “singing along” or introducing phase/dispersion/diffraction issues, ventilating their moving elements to assure “resonancefree” response, and using elegant electrically-simple secondorder crossovers (with Teflon-hybrid capacitors and air-core inductors encased in separate constrained-layer-damped carbonfiber chambers), he has sought to eliminate the céramique ringing/compression problem. How well he has succeeded—and he has, well—we will come to in a paragraph or two.
Vassilkov has done something else rather daring. While his 11" sandwich woofer and 7" membrane mid/woof use “conventional” (albeit highly select) ceramic diaphragms, he has chosen to use a 1.2" inverted-dome diamond tweeter for the treble range. For all their undoubted technical superiority, in the past I’ve generally felt that diamond tweeters stick out like diamond sore thumbs. Yes, they are incredible transducers in their own right, capable of exceptional resolution, bandwidth, and low distortion. The trouble is I’ve always heard them “in their own right,” as audibly separate and separable parts of the presentation. Hearing a driver—be it diamond, ribbon, or beryllium—as a separate element violates my first rule of high fidelity, which is that a speaker’s (or any playback component’s) primary obligation is to disappear as a sound source. Diamond drivers haven’t done that.
Neither, with exceptions, have woofers in ported enclosures—and the X Diamonds have (Vassilkov-designed, ’natch) ports. While I’ve heard my share of vented speakers that didn’t seem to have the usual excessive port peak (followed by that 24dB/octave roll-off below, oh, 50Hz or so), I’ve generally preferred woofers in well-designed sealed-enclosures, simply because the bass tends to go deeper more linearly and I don’t hear the driver/enclosure interface in the same way that I do with ported numbers.
Add all this up and in spite of the time and care and sheer brain-power Alfred Vassilkov lavished on his incredibly high-tech enclosure, the unbelievably persnickety attention he paid to driver selection, mounting, and damping, the many engineering awards he has won in Europe, and the very positive experiences I’d had listening to the Estelons at various trade shows here and abroad, my expectations about a home-audition of the X Diamonds weren’t sky-high. I figured—in spite of Vassilkov’s art and science—those ceramic drivers would still ring and compress, the ported bass would thump, and that diamond tweeter would tear what’s left of my ears off. However, as I’ve already hinted, I couldn’t have been more wrong.
Let me just say this outright: The Estelon X Diamond is the most perfectly phase-coherent all-cone loudspeaker I’ve heard in my home. Outside of a Maggie or a mini like the Raidho C 1.1, I’ve rarely heard its like (and one of those is a line source and the other a stand-mounted two-way). Not only does the X Diamond defy expectations by sounding like one seamless thing from bottom bass (and its bass goes very, very deep—into the 20–30Hz range—and does so with superb definition, grip, color, and clarity) to top treble (absolutely no sore thumb here), but it is the first multiway cone speaker I’ve heard which not only completely disappears as a sound source but manages to replace its presence with the presence of the room or venue in which the recording was made. Like Maggies or mbls, the Estelon X Diamond simply carves out a different ambient space within the ambience of your listening room and disappears within it. That space expands, as with a classic left-right A/B-miked stereo recording like Ian and Sylvia’s Four Strong Winds [Vanguard], or contracts, as with the great monaural recording of Penderecki’s spooky Cello Concerto [Muza] superbly played by the great cellist Siegfried Palm, as the source dictates. But whether the stage is narrow or wide, shallow or deep, stunted or sky-high, the X Diamonds just don’t seem to be “projecting” it (or any parts of it) from box or drivers. The only other time I’ve had this experience with a large cone speaker (well, cone and ribbon) was with the Scaena 3.4 at CES a couple of years ago. The X Diamonds are that free-standing and that “not there.”
Now, I know I’ve made this claim about a “disappearing act” before, about the Magico Q5, for instance. But, as our Mr. Pearson was wont to say, you don’t know that something is better until you hear something better. In its “disappearing act,” at least as a relatively large physical object, the Estelon X Diamond sets a new standard, chez Valin, for big, multiway all-cone speakers.