Floor Loudspeaker Reviews

Taste is a funny thing. Love cilantro? Millions swear it tastes like soap. Similarly, design cognoscenti will gush over a minimalist Scandinavian sofa that others dismiss as just a pricey plank with delusions of grandeur.

There's no accounting for taste, or so the truism goes. But arguing over preferences is exactly what many audiophiles do. Similarly, Stereophile reviewers are all about parsing and evaluating sound, and how a product looks isn't usually a big part of the equation. But I'll buck that convention and say that the radically shaped Estelon X Diamond Mk IIs aren't just the most visually sublime speakers I've laid eyes on; they ought to be part of the Cooper Hewitt Museum's permanent collection. Or MOMA's.

Got to be good looking
If the Estelons looked instead like upright coffins but sounded the same, I'd still praise them without reservation. But the sculpted shape—Brancusi meets Botero—is a big part of why I'm so smitten.

Now, I like shiny things, but I've heard and seen a hundred speakers with glossy automotive paint jobs that made them look merely attractive. Part of what puts the Estelon X Diamonds in a different category is in how the glasslike finish combines with its curves. A third component, light, makes the whole thing very nearly magical. Watch as both window light and floor lighting throw elongated vertical reflections along the floorstander's sloping, rounded flanks. When you move (or as the sun does), those lines change too, subtly and beautifully. There's also just something right about this design, in the way that a dolphin or a Fibonacci spiral is pleasing to look at. Modern technology has imposed an environment on all of us that's built from angles and other geometric shapes. The Estelons, by contrast, look organic, as if they weren't just engineered and constructed, but live-born at the same time.

A friend told me that the X Diamonds reminded him of bishops in a chess game. Others saw a modernist sculpture of a woman with a narrow waist and an ample bottom. And then there's the Reddit commenter who asked "Why do they look like giant sex toys?" Ouch.

I guess it's inevitable that plenty of people will call the Estelons something between homely and fugly. If you're among the naysayers, you could always comfort yourself with the thought that the Estonian speaker's remarkable sound is a direct consequence of its striking silhouette. Form follows function. Let's dive in.

Here come old flat top
The unique shape of the Estelons' enclosures—the antithesis of traditional box designs—is intended to avoid diffraction and other colorations. CEO and co-founder Alissa Vassilkova-Rajatalu noted proudly in an email to me that there are no parallel walls and that the surfaces are almost entirely curved. She also relayed that "Inside, each internal chamber is tailored to suit its specific driver." The company turns that approach up to 11: in order to combat microphonics and small vibrations, even the crossovers get their own subenclosures.

The absence of parallel surfaces cuts down on standing waves. The flat top of the speaker has a forward tilt of about 25°, which I'd like to think is also done to stop audiophiles from putting Marvel figurines or cacti there. Oh, the stories I could tell.

It's obvious that Estelons aren't manufactured by gluing sawed panels together. This kind of physique has to be molded. The company uses a proprietary marble-based slurry, a composite material that has advanced damping properties and combines density and solid mass, resulting in high rigidity. I asked Vassilkova-Rajatalu what she thinks of aluminum as a speaker-building material (footnote 1). She allowed that aluminum enclosures provide great stiffness, but "the flexibility of our molding process allows for shape modifications, which is more challenging with aluminum." That's a solid point. In traditional speakers, changing the bracing or the internal chambers requires the production of new, re-engineered parts—and often a change to the assembly process. Poured cabinets like Estelon's and Rockport's have the advantage that modifying a mold is technically pretty straightforward (if not necessarily cheap), and that design changes don't automatically imply production changes.

Speaking of design changes, the speaker's Mk II designation refers to several upgrades, including higher-grade crossovers that incorporate Mundorf Supreme resistors and SilverGold Oil film capacitors. As I mentioned, the crossovers, set at 75Hz and 2kHz, are now mounted inside dedicated subenclosures. The speakers are also equipped with new inverted diamond-dome tweeters whose bandwidth extends to 60kHz.

As three-way towers go, the X Diamonds break the mold (ha!). The 1" tweeter sits roughly at ear height below the 7" midrange driver, and the two are mounted just millimeters apart, presumably so they'll act as a kind of point source. The 11" woofer is mounted 27" lower, in the thickest part of the enclosure, 5" from the bottom edge. That lets the woofer couple acoustically with the floor. According to Vassilkova-Rajatalu, this approach "maximizes the efficiency and output of the woofer, for a more coherent bass response and an even distribution of standing waves throughout the room." As frequencies rise above 100Hz, sound gets more directional, and the placement of midrange drivers and tweeters becomes crucial. Unsurprisingly, the Estonian team has thought this through: "Our mid-woofer and tweeter are positioned higher in the cabinet to minimize reflections from adjacent surfaces. That improves stereo imaging and also enhances the coherence of sound from low bass notes to the highest harmonics."

Each speaker is heavy—190lb—which helps provide "both static and dynamic stability." Thankfully, getting the X Diamonds into your home and setting them up is less of a struggle than their weight implies. They ship in flight cases on casters. Once the cases are inside, upright, and unlocked, the speakers are ready to be rolled out—they're on wheels too—via a clever built-in ramp. Similar to my reference Focal Scala Utopia EVOs, once you're sure where you'd like to position the speakers, you're encouraged to remove the casters and insert the supplied spikes.

After four, five days of trial and error, the midnight-blue towers ended up 8' 4" apart (measured from the drivers' center) in my 21' × 15' room. Their rear ports were 5' from the front wall; the distance to the sidewalls was 39"; and when I sat in my chair, my ears were 10' 2" from the front baffles. Toe-in was slight: 3°–4°.

It was perhaps a good thing that I didn't read up on ceramic drivers until I'd already had the speakers in my system for a couple of months. Estelon sources the X Diamond drivers from Thiel & Partner, the manufacturer of the acclaimed Accuton transducers. (This Thiel is no relation to the now-defunct American speaker brand, nor to A.N. Thiele of the well-known Thiele/Small loudspeaker parameters, footnote 2.) The German company states on its website that its ceramic and diamond drivers are somewhat vulnerable to excessive excursion: "Ceramic and diamond cones are brittle and therefore sensitive to severe overload conditions (ie, excursion of more than double the rated Xmax)." (footnote 3) On top of that, "both [types of drivers] are sensitive to touching by fingers or hard items—comparable to an eggshell."

I had remained in the dark about these susceptibilities. From time to time, in the mood for something raucous, I'd tortured the Estelons with a metal mixture of Rage Against the Machine, Led Zeppelin, and Tool, all at admittedly unreasonable volume levels. In other words, I never walked on (ahem) eggshells around the Estelons—and luckily, the speakers survived the onslaught just fine.

About that "sensitive to touching" caveat: There's no cause for worry, as each X Diamond driver is covered with a rugged honeycomb black metal grille (convex for the tweeter, concave for the midrange and woofer). It isn't user-removable unless you bring a toolkit and some serious elbow grease. The openings in the grilles are too small for even a knitting needle to poke through, let alone a crayon, a child's fingers, or a cat's claws.

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Footnote 1: Think of Magicos, Piegas, and some of YG Acoustics' pricier offerings.

Footnote 2: See en.wikipedia.org/wiki/Thiele/Small_parameters.

Footnote 3: Xmax is short for maximum linear excursion. The numeric value expresses to what extent a speaker's output becomes nonlinear when its voice coil moves beyond the magnetic gap.