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Hard sell? Packaging a cheap €329 electronic crossover box charged to perform critical A/D/A conversion with a €10K pair of ambitious loudspeakers seems like a raw deal. Until you hear how well it works. I had a €4.000 active analog crossover from WLM to compare against. This aspect admittedly remains a perception hurdle for purists and snobs. I'd suggest we move on rather than getting embroiled in that discussion.

Gain matching: When you run two amps of very similar gain and output power as I did with the F5 and J2, you may need to set the DBC-12's input sensitivity to 1 or 2V to build in enough headroom for LF compensation (but you don't want to overdrive those inputs either). When I ran the 300wpc April Music Stello Ai500, I switched that value down to 3V and still ran the electronic box at minus 8dB output.
While the paralleled woofers theoretically enjoy a 3dB sensitivity advantage over the midrange, this clearly doesn't hold true at bass frequencies. If you listen loud and plan on significant LF compensation, a more powerful bass amp becomes mandatory.

The multi-layer menu of the DBC-12 proved very easy and intuitive. It made noise-free alterations on the fly a snap.

Once I'd spent a few days investigating the various possible profiles and their effects to dial in the most linear baseline with a minor upward trend going down—I also altered Boenicke's 4th-order low-pass preset to the shallower 2nd-order option for a more linear transition—it was ultra convenient to nudge the crossover's master gain at its hinge up or down by a few clicks to best suit the type of music, average listening level and whim of the moment. Only those without such flexibility would even dream of knocking it by standing on a soap box.

The antithesis of dry: By directly energizing the ambient field to a far higher degree than conventional direct radiators, the SLS plays it bigger, fluffier, less articulated and razor-edged. When sitting within an equilateral triangle—i.e. closer than at the apex of my usual elongated triangle—these sticks created an unusually connected milieu. It made the listener more a participant in the ambient field than observer. I wasn't exactly enveloped but definitely connected to a heightened extent with the energized sound bubble behind the speakers. The soundstage was more immersive. I felt part of the same viscous fluid which pulsed behind the speakers. This was akin to standing hip-deep in the ocean during a lucid moment and feeling as though one with it despite not being submerged This was a fundamental shift and a lot closer to 'live' than those overdamped hifi facsimiles which are beamed as though by laser into the listening area. This was juicy, redolent and fluid rather than ultra taut and damped. It thus had a pleasing degree of billowing thrown in which nonetheless took some time getting used to as it contained greater general room resonance (rather than hot spots).

Don't mistake this description to imply that the SLS was sloppy. With its woofers' magnets essentially cradled inside their opposing walls—the woofers aren't perfectly horizontally opposing for lack of depth but they are offset as narrowly as possible—there's hardly any lateral air space to excite and pressurize. It all goes down the tube which isn't a heavily flared back horn for resonant gain but a quite narrow empty transmission line that's clearly tuned for maximum damping. Even during stout output serious infrasonic transients, woofer excursions proved nicely self-regulated and limited to suggest efficient acoustic power transfer.

Viva la difference. Still, how sidefiring woofers energize a room is different from direct radiators. The initial attack's instantaneous spike doesn't communicate with the same impact. Unlike cyborg bass with its ultra-dry transient slam and whipping/slashing action, SLS bass was closer to live - big, rotund, massive and part of the space rather than isolated from it like a specimen on a needle. But because this more evenly distributed energy—causing plainly less room modes—wasn't generated from big woofers, I did not feel that wall-of-sound kick which bad-ass woofers produce. This presented a most interesting dichotomy: to hear big bass which nevertheless lacked a familiar ingredient of bigness. The more appropriate term actually is aggression, that carefully cultivated bass brutality which some correlate with impressive bass. Regardless of how you personally relate to that particular very snappy and bone-dry quality, here it was absent.

This general difference of interacting with the room also manifested in another novel fashion. Increases in overall volume didn't track as usual. With conventional speakers, a raise of volume immediately increases the sound pressure in the seat. With the SLS, the energy filling the wide open space behind the speakers increased right away, over there. But there was a somewhat delayed reaction at the ear. Where two or three clicks up normally produce all the intended lift, here it took considerably more (which was obviously related to my setup of having no effective wall behind the speakers).

Added to these various differences was the combined surface area of those paralleled flat-cone 3-inch tweeters. Their compound air-moving action is well in excess of ordinary 1" domes. This greater capacity increased top-end dynamic expressiveness to telegraph output changes very rapidly. It countered the less direct character of the reflected omni bands and maintained localization stability of the virtual performers. It also communicated the encoded energy of percussive events to retain finesse and twinkling sparkle on cymbals, brushes and the like. While I originally wondered about the presence of that second tweeter when I first saw the speaker at the Zürich show, I now understood how a single small tweeter would likely not sufficiently balance out the considerable energies which this speaker directs at reflective* surfaces.


* Theoretically at least, this would seem to favor reasonably 'live' over heavily damped rooms.

Amidst this otherness of presentation and approach and after a few hundred hours of use, an unexpected asset of the SLS was its tonefulness. Partly because of its 'actively room-interactive' nature, the SLS had gorgeously saturated wet tone already when fronted by a transistor preamp and transistor amplifiers. One naturally also suspects those Monacor drivers and the solid wooden enclosures but I particularly considered the dispersion character responsible.

Sven Boenicke's SLS doesn't merely look different, it also sounds it. What distinguishes it from pure omnis like Duevel are the front-firing tweeters which guarantee well focused and sorted performer locations. There is nothing vague or ambiguous about positioning within the soundstage. But there is a fundamental difference in how the soundstage is activated. It becomes a container and disburser of acoustic energies, not a passive canvas. This distinction is profound enough to compel philosophical discussions. If this is right(er) vis-à-vis the live experience, is conventional front-firing hifi wrong?

I'm not about to answer that in this context. I'm presenting this question merely to underline that this difference is real and significant. It's not superficial. Most of us are conditioned to relate to the other sound as correct just because it's in the vast majority. When confronted with a different proposition, preconceived notions, habits and engrained preferences get challenged. Without proper acclimatization—to 'forget' the old and deal with the new on its own terms and merits—one misjudges. No matter the final conclusion which will differ from person to person, it definitely involves coming to terms. Let's take a quick intermission then for a pictorial presentation.