"As you've tracked, we took our time with Druid MkVI - significant time with much outside beta testing including several big shows. The Munich event where you got a taste was the first public debut. The vast majority who heard the demo set were impressed; just perhaps a touch too much so. Not that the demo sets weren't musical but their playback did have a hint of bombast. It took listening with a quiet mind and poised disposition to really put a finger on what might need resolving. There was a little lack of 'truth', a bit too much emphasis in resolving the transients and odd-order harmonics and not quite enough blood and guts. It was either the new widebander; or changes made to the Radian 850 tweeter; the cabinet; or some combination. In testing—and that took a good deal of time—we found the main issues to be in the cabinet. We ended up removing a good deal of the carbon fibre and increased the diameter of the Birch to raise vibrational damping since there is no real damping in carbon fibre or epoxy. There were other changes too but the cabinet was the meat of the issue. Here's an outline of the changes made from the beta Druid VI you spent time with in Munich and what we are shipping and what you have for review:
  • Increase the cabinet materials' damping qualities through the reduction of carbon fibres and increasing the mass of the Birch dowelling.
  • Reduce the infusion epoxy within the layup of the cabinet.
  • Add a fine layer of damping between finish and cabinet.
  • Increase the length and ratio of carbon nano tubes on the widebander's membrane to better control cone modes and further increase cone propagation velocity.
  • Increase lap-fit tolerance between the full-ranger driver and cabinet to better distribute and reduce stress risers within the cabinet/driver interface.
  • Add rubber damping gasket between full-ranger driver and cabinet interface.
  • Remove carbon nano tube skins on the tweeter diaphragm.
  • Increase the volume and shape of the tweeter's rear air chamber to broaden and reduce amplitude of the standing waves within that cavity.
  • Significantly increase damping gasket mass and area between the Radian tweeter driver/cabinet/tweeter lens.
  • Remove the silver 0.1µF by-pass capacitor from the high-pass filter network.
  • Add swiveling leveling footers complete with high-density rubber pads to help damp and impede cabinet/floor vibration interplay.
  • Add small access holes to the base to allow for easy loudspeaker leveling

 
Design bias. If we harvest the preceding info including Sean's interview with John Atkinson, we arrive at a focus on the time over amplitude domain plus power efficiency. Most modern speaker designs go after flat amplitude response. Power efficiency rarely factors at all. Regardless of where in this discussion we plant our flag of allegiance, any position has to be a compromise. That's just common sense.


With the Druid's priorities clearly stated—including its lack of any corrective filtering on the widebander—one expects minor deviations in its amplitude linearity as a matter of necessity. One also expects audible differences to the majority of speakers which are groomed for maximally linear on/off-axis amplitude response. With a 10.8" driver going up into the low treble, one expects progressive beaming, too.


What would the Druid VI offer in trade? What type of listener might favour what it does better or just different? Might music genres or SPL factor? At right we see the standard binding posts plus a self-locking SpeakOn port. That's for matching Zu speaker cable which now bypasses certain internal solder junctions for the most direct connection. Zu dispatched such a 3-metre pair [above] to let me report on sonics vis-à-vis our spade-terminated Event MkII. As shown, spikes particularly on thick carpet may still be used in lieu of the ball-decoupled flat footers.


To wrap up our lengthy intro, one appreciates how a commitment to no filter parts for the majority bandwidth limits any designer's compensation of response irregularities plus voicing to the mechanics of driver/enclosure tweaks. Unlike a simple notch filter or low-pass on the widebander to 'cut out' any misbehaviour in its upper reach, the Druid VI had to pursue corrections with mechanical addresses. As this narrative showed more than once, prototyping various cabinet iterations under sundry conditions took far more time than just toggling between different filter parts with alligator clips for instantaneous A/Bs of a conventional crossover whilst various simulation software had already defined the allowable parameters.


Also, stock or even customized drivers arrive as ordered from the vendor. Not this Druid's. Zu's approach to its 50Hz-10'000Hz widebander with whizzer cone entails an in-house rebuild and chemical treatments. The latter require a controlled environment and specialized kit to administer. And there's no simulation software for nano coatings, either. This crew even rebuild a costly premium tweeter with self-sourced magnetics and rear chamber alterations. Clearly the trial and error implicit in this approach isn't every maker's bag. Team Zu don't do it the easy way. It's another reason why the widebander genre is so sparsely populated. It's a lot easier to get a conventional speaker into the ballpark. Buying into the Druid VI's iterative learning curve wasn't for the faint of heart nor those pressed for time. Now we arrive at delivery:


The seriously strapping shipping boxes revealed thinking construction. Flipping the long lid showed massive foam liners with cloth-covered inners to require no shrink wrap or any other protection on the cabinet's fine lacquer. With the foam glued to the bottom flaps, opening them up easily made room to stand the speaker up. At that point (or rather, at four points)...


... the new flat-bottomed swivel footers were superb on our faux parquet floors. They meant zero fuss with spikes and their receivers whilst making for easy leveling from above. With 1'000 hours already clocked, this traveling pair only needed to return to 19° C room temps to make up for a few days in high-moisture storage whilst waiting for lazy customs clearance and a long Easter weekend lock-down to run their course. Time for a friendly match against our Druid V.


For that, the long-wall setup in our 2-channel media room was more conducive than the short-wall layout of the main system. Anchored by an Oppo BDP-105 feeding digits to a Vinnie Rossi Lio with tube-less AVC, this system could accommodate two sets of speakers cheek to cheek. That would be ideal for smooth A/Bs before the new VI now at $10'000 had to test their mettle against our Audio Physic Codex in the same price league. As a premium 4-way multi-driver effort with custom Wavecor drivers, those are from that other part of speaker town where the majority of buyers live. They'd make for a meaningful comparator. But first, the newcomers would have this floor to themselves to acclimate to their new surroundings and me to them.


Starting with Druid V, the prior logo badge on the front baffle had migrated as an upward engraving to the plinth. Druid VI inherited that convention for very understated branding. Not that this speaker needs identifiers. Its signature profile has effectively become the brand's trademark. Given its inherent rectangulosity, that's quite the feat. Where competitors rely on curves and facets of varying complexity to distinguish themselves from the crowd, the Druids have always managed to do so with purely right angles and flat panels. It's why despite its upgrades, Druid VI stayed true to form. Without it, it wouldn't be a Druid.


If you haven't yet made the connection as to why such a heavy plinth, consider the location of the widebander at the very top of a very shallow enclosure. With its forces not canceled out by an opposing driver, they needed a structural counterbalance to ground out. Obviously the plinth also enlarges the footprint to serve a related purpose. There's never any chance of a hoovering 'driveby' accident. At ~100lbs each and four-square leveled, these won't budge.
... to be continued...

Zu Audio website