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This review first appeared in the June 2010 issue of hi-end hifi magazine fairaudio.de of Germany. You can also read this review of the Diapason Adamante MkIII in its original German version. We publish its English translation in a mutual syndication arrangement with the publishers. As is customary for our own reviews, the writer's signature at review's end shows an e-mail address should you have questions or wish to send feedback. All images contained in this review are the property of fairaudio.de or Diapason. - Ed.

Reviewer: Ralph Werner
Sources: Analog – deck - Acoustic Solid MPX; tone arms - Phonotools Vivid-Two, SME M2 12-inch; carts - Denon DL-103, Ortofon MC Rondo Bronce, Zu Audio DL-103; phono pre - SAC Gamma Sym; digital - audiolab 8000CD, HIFIAkademie cdPlayer
Amplification: Pre - Octave HP300; power - Electrocompaniet AW180; integrated - Denon PMA-2010AE, Lua 4040 C
Loudspeakers: Ascendo System F, Thiel SCS4
Various cables, racks and sundry accessories
Review component retail: €3.950/pr

Rainer Israel of Friends Of Audio first noticed the Diapason brand visiting Mastersound’s Northern Italian cabinet maker who crafts the valve amp’s wooden cheeks. "While in the shop I noticed absolutely gorgeous and quite far-out speaker chassis". Those piqued his interest. He quickly contacted Alessandro Schiavi responsible for the Diapason speakers. Being into ‘made in Italy’, the cosmetic, tactile and acoustic virtues of the speakers convinced him to take on importation. Though the brand dates back to 1987, I wasn’t hip to it. It's impossible to know everything of course and for Germany, Diapason is far more recent to save my face.


Still, I can confirm the magnetism of interest this speaker radiates.  And, who else works in solid wood and finishes off so heavily faceted? The company is based in Lombardia, more precisely the city of Brescia, about 30km west of the Garda Lake where Schiavi finished his piano, organ and electro-technical studies during the 80s and stayed on. Arriving at hifi came via the pro detour. As recording engineer for various studios, he soon wanted to master with his own—read, better—location monitors. When the outcome attracted attention outside the studio, a business developed which in the spring of 2010 holds three models in its Reference Series. The Adamante sits in the middle but is perhaps the most mature. It's been in the lineup for 20 years. The current incarnation goes by MkIII. While form factor and concept remain unchanged from the beginning, driver complement and crossover didn’t. Today’s transducers for this Southern belle come from the North – Norway’s Seas for the 12cm poly membrane mid/woofer, Denmark’s ScanSpeak for the 19mm silk dome.


Either driver incorporates proprietary wrinkles and undergoes better than 1% pair matching. At 4.600Hz, the hand-over frequency is unusually elevated. The network is strictly purist with an LC filter on the tweeter – e quello è esso.


Behind this minimalist choice sits Diapason’s Direct Drive Technology or DDDT in proper marketing lingo. The mid/woofer is wide open and couples it voice coil directly to the amplifier via the lower biwire terminal and oxygen-free silver-plated copper hookup wire by van den Hul. It runs no filter of any kind.

Schiavi cites three advantages – audibly higher transient fidelity, lower sensitivity losses and the absence of passive filter phase shifts. Direct drive with off-the-shelf drivers is problematic he said but close collaboration with Seas’ engineers netted a properly massaged transducer. Precise details remain the company’s secret. The cabinet volume, loading and driver behavior add up to an acoustical 6dB/octave function while the tweeter comes in more steeply at 12dB/octave. The choice of wood is far from secretive – Walnut. Contrary to certain speaker beliefs, it’s massive solid wood to boot.

Schiavi invokes "musical attributes" as rationale. That’s frankly neither here nor there. It’s all about resonance minimization and tuning when remaining resonances are channeled into the most ‘harmonious’ spectrum. While there’s possible overlap with the THD behavior of amplifiers and their effects on ‘musicality’, Diapason doesn’t invoke it.


Besides dissimilar thickness from 2 to 4 centimeters, the Walnut carcass’ interior geometry mirrors the faceting on the outside. This counters basic standing waves with many angled surfaces. The photo assemblage on the next page shows the construction process.


Besides its resonant behavior, Walnut has an advantage over other woods when properly cured. It retains less moisture. Since wood lives, subsequent expansion and contraction is common but to be avoided in a speaker lest it develop cracks. Diapason’s track record is clean. They purchase only wood properly cured over 20 years and add two more years in their own shop just to be sure no moisture remains.

The usual brick shows six surfaces, Diapason’s Adamante sixteen. This jewel-type profile minimizes edge diffraction and, as per Schiavi, improves point-source behavior. One could even view this wooden two-way as a filterless widebander with treble augmentation. After all, the mid/woofer alone covers a full eight octaves, admittedly little below 40Hz. Still, that’s very impressive bandwidth for one driver.
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