Audio Physic Kronos loudspeaker:
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The crossover control's five positions adjust the woofers' low-pass frequency between 250Hz and 300Hz, allowing you to make subtle distinctions between bass that's lean and tight and bass that's somewhat warmer. You can also disable the crossover, if you want to insert an external crossover between the two modules. Also included are: a Phase button, to invert the subwoofer polarity; a Subsonic button, for LP playback, if needed; and three presets, for Small (25m²), Medium (40m²), and Large (>40m²) rooms. With the presets, you can set all parameters "in the ballpark," so you can have a reasonable starting point from which to customize the bass performance.

You can play with and tweak the Kronos all you want—or, once you've got the speakers sounding the way you like, you can disconnect the remote and the settings will remain in memory. But this level of adjustability is a double-edged sword: yes, it allows you to fine-tune the bass performance, but it also allows you to obsess over the many variations in sound performance you can achieve. Hand-wringing neurotics and obsessive-compulsives (ie, most audiophiles) may wish to have the speakers professionally set up and the remote control removed from the premises.

My room doesn't have a room bump, but it does have a suckout at about 67Hz at my listening seat, and has trouble developing really deep bass. I was able to compensate for these problems by upping the bass 3dB, setting Room Gain to just above the suggested range for a medium-size room, crossing over at 250Hz, and inverting the woofer phase. The improvement in bass solidity, focus, and extension in the Inverted position was so intense and noticeable that I had to double-check my speaker and jumper connections. They were correct.

Strap on your seatbelt
Ever since Audio Physic was founded, their slogan has been "No loss of fine detail." The Kronos shouted that slogan in caps. It had an effervescent quality that has been matched in my home listening experience by only the $41,500/pair Rockport Antares I wrote about in August 2002, and maybe by the $23,500/pair Aerial Acoustics 20T (which I reviewed in the April 2004 Stereophile). Notes appeared with startling clarity and transparency, then vanished without a trace. When I played Johnny Cash's American IV: The Man Comes Around (2 LPs, Lost Highway/American 440 063 336-1), each string of a strummed guitar, for instance, produced a hyper-pronounced physical sensation, as if I was surfing the strings on the guitar pick. There were times I felt more like Johnny Cash's dentist, so startlingly clear was every twitch of his mouth, teeth, and vocal cords.

When the bass was properly dialed-in, there was no trace of warmth, thickness, or midbass overhang. Bass transients were delivered with exceptional clarity and snap, while the resulting low-frequency follow-through sounded robust, full, and on pitch. You can add extra bloom by fiddling with the controls, but then you'd miss the points of the Kronos: clarity, speed, transparency, and detail, without added brightness or peakiness.

This was the first chance I'd had to hear ScanSpeak's ring-radiator tweeter (Audio Physic's Avanti III used the Vifa version). In this iteration—and in the Kronos, at least—the tweeter was satisfyingly sweet, airy, smooth, crystal-clear, ultra-extended, and capable of creating an enormous sonic picture free of hot spots, etch, obvious peakiness, or other mechanical glitches. If anything, the Kronos was on the mellow side right at the top, but only slightly.

Audio Physic makes a big issue of decoupling the mid- and high-frequency drivers from the baffle in most of its line, using a variety of mechanical techniques. Whether it's the decoupling, the coaxial mid/high driver, or some other aspect of its construction, the Kronos was among the least "boxy" box speakers I've heard. The two of them produced a soundstage of enormous proportions—even more substantial than that of the Aerial 20Ts. I'm not suggesting that the ring-radiator tweeter resolved high-frequency information as fully as the 20T's ribbon tweeter—it didn't. But it came very close without suffering the ribbon's restricted vertical dispersion.

Acoustic Sounds' spectacular two-LP, 45rpm edition of Art Pepper Meets the Rhythm Section (AJAZ 7532) demonstrated much of what's special about the Kronos. With Miles Davis's rhythm section (Red Garland, Paul Chambers, Joe Jones) in the right channel and Pepper in the left, this 1957 recording would arguably have sounded better in mono, but timbrally and dynamically—and, of course, rhythmically—it delivers the goods. Through the Kronos, Pepper's lines had both the lithe airiness you expect to hear from the alto sax's top end, plus the meatiness in the lower registers. As Pepper twisted and turned up and down the instrument's tonal and dynamic range, the Kronos cornered like a fine German sports car, producing a round, startlingly convincing, 3-D image of Pepper playing in my room.

On the other side of the room, Philly Joe's drums sparkled and snapped on top, with a popping snare sound sufficiently well-developed to raise the hairs on my neck. But when he hit the kick drum, the full explosive weight was there, with the crack, speed, and texture of the real thing. When I cranked the Kronoses way up, they didn't flinch. They just got louder, fuller, and bigger, producing the most convincing illusion of a drum kit—especially the snare—being played that I've ever heard in my room.

When I turned down the volume and played a solo guitar recording—say, one of Laurindo Almeida's classic 1950s discs, such as New World of the Guitar (Capitol P8392)—the big-speaker bombast fell away, revealing a transducer capable of small, subtle gestures. Despite their weight and size, the Kronoses could disappear as well as any of the smaller Audio Physic speakers, to produce a compact image of realistic size sitting before me—in this case, an image of Laurindo Almeida. Even at low volumes, the Kronos was capable of delivering superb transient clarity, Almeida's fingers plucking the gut strings with just the right balance of snap and weight to produce a realistic tonal and textural image.

Fun with the Kronoses was going from something like the Almeida album to Classic's 45rpm edition of The Weavers' Reunion at Carnegie Hall 1963—in other words, going from an intimate "in-room" solo performance to sitting mid-orchestra at Carnegie Hall. The transparent, effervescent quality of these speakers, combined with a bottom-end weight free of midbass bloat and their unusually extended presentation of stage height, produced a ghostly-real picture of this familiar concert recording. Realistically sized, delicately delineated three-dimensional images in a convincingly large space—thanks to the Kronos' low-frequency extension—made this an unforgettable listening experience. Sometimes Ronnie Gilbert's voice can sound piercing on this recording, and sometimes Pete Seeger can sound thin and without body. The Kronos produced an ideal overall balance both on this recording and on the 45rpm edition of Belafonte at Carnegie Hall, which may have been the highlight of the month's audition.

While rearranging my record shelves, I came upon some records I'd never played, including a German ARS reissue of a classic Telefunken Das Alte Werk LP from 1964: J.S. Bach's Brandenberg Concertos 2, 5, and 6, played on original instruments (SAWT 9460-A). Brandenburg No.6 is scored for low strings, with violas, violas da gamba, and cellos. These were rendered rich, lustrous, silky-smooth, and free of congestion or overhang, each instrument given convincing low-frequency weight and clearly defined, tonally and spatially. I'll be curious to hear how the Wilson Audio WATT/Puppy 7s, with their warmer bottom end, handle this difficult-to-reproduce material.

I'm not a big opera fan, but I had a feeling the Kronoses would do a magnificent job of delivering Richard Mohr and Lewis Layton's spectacular-sounding production of Puccini's Turandot, with Birgit Nilsson, Renata Tebaldi, Erich Leinsdorf, and the Rome Opera House Orchestra (LPs, RCA Living Stereo LSC-6146). They did. The speakers dramatically delivered the full weight of the orchestra with the chorus placed behind, well-focused in space. Even more impressive was the believable, transparent, and exceptionally coherent renderings of the male and female soloists—free of brightness, etch, and sibilant excess. I've never heard this recording sound so rich and full yet so detailedly three-dimensional, spread across a soundstage that stretched well behind the baffles.

Not everyone's sonic nirvana
Partisans of the Audio Physic "house sound," will be thrilled by what Gerhard and Diestertich have achieved. The Kronos delivered the goods from the very top to the very bottom, and its array of controls mean it can be harnessed to provide tight, well-controlled deep bass in most rooms—though in my room I know I didn't get the full weight of which I know the speaker is capable. It was frustrating to play a 20Hz tone and hear stomach-curdling low frequencies to either side of my listening position, only to have them fall off a sonic cliff when I sat down in my listening chair. This was my room's fault, not the Kronos', but it points out one of the disadvantages of attaching a powered subwoofer to a mid/high-frequency unit: Where a speaker images best is not necessarily where it delivers the best bass performance.

Still, the Kronos will not be everyone's sonic nirvana. Like most Audio Physic designs, it did not sound romantic. The Kronos sacrificed midband lushness and texture in favor of an almost acidic transient snappiness (though using a tube amp, as I did with the Music Reference RM-200, tamed that quality somewhat). If you like your sound on the soft-palate, Merlot side of things, the Kronos will probably not be for you. In my room, there was a slight but broad elevation in the presence region that helped give transients their snap and definition, and added a bit of spotlighting to percussion and the percussive elements of the sounds of other instruments.

Also, because the point-source tweeter/midrange driver is almost 4' off the ground and aims straight ahead, image height on some material seemed unusually high; sometimes, the sound appeared to be coming from the confines of the coaxial driver. Careful adjustment of bass level and crossover point can minimize or eliminate that problem, but I found that, no matter how I adjusted the Kronoses, certain recordings with concentrated upper-midband energy created a sensation of the sound coming from the round grille cover. These problems might not occur in larger rooms, where the listening position can be farther away from the speakers than was mine.

Finally, as with any high-resolution product, associated equipment will have a profound effect on the final results with the Kronos. The AudioQuest Kilimanjaro speaker cables, which had worked so well with the Wilson WATT/Puppy 7, were a bit too lean for the Kronos. Switching to the latest iteration of Harmonic Technology's Magic Tweeter cables mellowed things out a bit without losing resolution or transient clarity. A good tube amp on top was the ticket for added midband warmth, although, because the woofers take their cue from the amplifier's bass performance, there was some loss of low-frequency punch and definition.

Conclusion
$65,000 ought to buy you the whole ball of sonic wax, and the Audio Physic Kronos delivers it in a relatively small package while opening up your amplifier possibilities to some small, sweet-sounding tube devices. I'm confident the Kronos' measured performance will only hint at the speaker's explosive transient and dynamic speed, its extraordinary midrange clarity and transparency, and its stomach-wrenching low-frequency extension, weight, and suppleness. And measurements can never describe the Kronos' substantial, coherent, three-dimensional soundstage, or its exceptional image solidity and focus. All of that awaits those lucky enough to be able to afford them.

Which brings me to the question of value. I have no doubt that it cost plenty to build the Kronos' complex, curvaceous, raked cabinets. The Kronos is a complex piece of high-tech componentry, and anyone who understands how such a product is developed, built, marketed, and delivered will appreciate the expenses involved. Nonetheless, you can get, say, the Aerial 20T for $23,500/pair, and two Aerial SW12 subwoofers—which I believe can easily compete with the Kronos' powered woofers—for another $11,000. Spending $65,000 for a pair of Kronoses thus becomes difficult to justify with anything other than "form factor." This may well be reason enough. Getting roughly the same performance from two spectacularly sculpted towers as from four boxes, two of which are literally boxes, can make a big difference in many situations—especially those in which money is not the overriding factor.

The Kronos loudspeaker takes the Audio Physic mission statement to its logical conclusion. I thoroughly enjoyed my more than a month with the Audio Physic Kronos. Whenever I thought of it as the greatest rock'n'roll speaker I'd ever heard—which it is—I'd put on a delicate solo acoustic recording, and the Kronos excelled at that as well. Rich and sensuous? No. "No loss of fine detail"? Yes.

Mission accomplished.