Audio Physic Caldera III loudspeaker

More, I think, than any other link in the audio chain, loudspeaker designs tend to reflect the personal preferences, opinions, and philosophies of their creators—think Henry Kloss, Paul Klipsch, Rudy Bozak, David Wilson, Jon Dahlquist, Arnie Nudell, and Amar Bose (just kidding). Consider, if you remember, where Ken Kantor took Acoustic Research when he took over AR's design reins. Might as well have called AR NHT, for all that the new designs followed the old.

Audio Physic long reflected company founder Joachim Gerhard's restless mind, which could be seen and heard in his wildly divergent designs. His Medea ($50,000/pair) used the unusual, star-shaped Manger driver. The original Caldera ($19,000/pair, reviewed by Martin Colloms for Stereophile in August 1997) featured three Scandinavian-sleek stacked modules, one each for the bass, mids, and highs, with an asymmetrical tweeter housing and 90°-offset midrange drivers in the central module. Gerhard's downline speakers were conceptually more uniform: all had narrow baffles, epitomized by 1995's Virgo II ($5500/pair), an instant classic that's still sought out. As you can read in my review, the Virgo had minor flaws and colorations, but taken all together, it was magic.

But the Virgo II's success became a problem for Gerhard: his far more expensive original Avanti model may have been a better design, but at twice the price, it wasn't that much better. Manfred Diestertich took over from Gerhard developing the sophisticated Avanti III ($13,000), a successful speaker both sonically and in the marketplace. I owned a pair for a few years following my review in August 2001 and enjoyed them greatly.

Gerhard is no longer associated with Audio Physic, which now has new owners, Willi Hegener (who has been associated with the company for many years), Karl Becker, and Dieter Kratochwil. Manfred Diestertich is solely responsible for the subject of this review, the new Caldera loudspeaker. The last Audio Physic speaker I reviewed was the Kronos, in the June 2004 Stereophile. The Kronos was an ambitious new design with an active subwoofer section. It incorporated an adaptation of the company's previously developed subwoofer technology with Diestertich's string-suspension–based coaxial driver. However, the speaker's price got completely out of control. Originally designed to sell for around $45,000/pair in the US, its complex cabinetry and the falling dollar meant that it ended up costing $64,995/pair. The early-production unit I reviewed had some minor unfinished physical and sonic qualities, and while these have apparently been fixed, the Kronos remains a tough sell. At $24,000 less, Wilson Audio's MAXX2 is, in my opinion, a much better speaker and a much better value, though the Kronos is more visually attractive and less industrial looking, and is powered on bottom by one of the most sophisticated bass-driving systems currently available.

Little Kronos? Big Avanti III?
The Caldera incorporates much of the Kronos' technology, at a lower price: $30,000/pair. As Manfred Diestertich did with the Virgo III (footnote 1), rather than update the original Caldera inherited from Joachim Gerhard, Audio Physic's new head has designed an entirely new speaker. The upside is a clean break with the past and a fresh design using the new team's latest thinking and innovations, combined with elements of the Avanti III.

The rationale behind the new design is clear. Looking like a small Kronos or an Avanti III on steroids, the new Caldera represents an attempt to establish a distinctive, recognizable family look for the upper end of the Audio Physic line. The strategy is not without risk: While the Avanti III was a success, the Kronos hasn't exactly taken the audio world by storm (at least not in America), and there's always the chance that the new Caldera will be seen as merely a bigger Avanti III costing more than twice as much.

Photos don't do justice to the Caldera's scale. Though considerably bigger and heavier than the Avanti III, it doesn't seem so, which is testament to its graceful curves and cleanly rendered lines. Designed to be Euro-friendly, it will fit into the smaller living spaces found overseas and obviously into small and large spaces in America.

As they did with the Avanti III and Kronos, for the Caldera Audio Physic used the Danish Hornslet speaker factory's patented Hornflex technology to create the speaker's curving cabinet from a single sheet of MDF. Aside from looking great, the curves minimize the internal standing waves caused by parallel surfaces. The baffle's rake adds another level of complexity to the CAD design, which also features a wraparound skin of veneer. The cabinet's interior is extensively braced by a substructure that also serves to secure the four side-mounted bass units. It's easy to take such a complex design for granted, so clean and simple does it look from the outside.

Despite its deceptively compact appearance, the Caldera stands almost 4' tall and 20" deep and weighs about 132 lbs. Compared to the Avanti III, though, it's a far more complex design, and features the unique coaxial String Suspension Concept (SSC), a string-supported midrange/tweeter driver developed by Audio Physic for the Kronos and covering a range of 150Hz–40kHz.

The coaxial drivers are the same 1" Scan-Speak ring-radiator tweeter and 7" Active Cone Damping (ACD) ceramic-coated aluminum-cone SEAS midrange used in the Kronos. Whether for reasons aesthetic or sonic, the tweeter, framed by its machined aluminum face plate, appears to "float" in the center of a piece of black felt that masks the string mechanism and the midrange cone.

While the Kronos' coaxial driver is decoupled from the front baffle and attached to a secondary baffle mounted within the cabinet, the Caldera's coaxial unit appears to be conventionally mounted on the front baffle and set in an elongated aluminum frame. This frame also contains the 7" SEAS lower-midrange unit (equipped with foam phase plug), a version of which is used in the Kronos as a side-firing pair of woofers.

The Caldera's "push-push" side-firing low-frequency units comprise pairs of active 10.6" ceramic-coated aluminum-cone Vifa woofers and 10.6" Peerless Nomex-cone passive-radiators that feature what appear to be carbon-fiber dustcaps. The passive radiators look like drivers but actually function as reflex ports. The woofers cross over to the pair of midrange drivers at 150Hz, the lower unit rolling off at 6dB/octave at 500Hz, the coaxial unit operating up to the tweeter handoff point at 2.7kHz.

Footnote 1: I reviewed the Virgo III for Stereophile Guide to Home Theater in a 5.1-channel configuration, while Brian Damkroger reviewed it for Stereophile in September 2003.
Audio Physic
US distributor: Soundquest
New York, NY
(212) 731-0729