Srajan Ebaen
Financial interests: click here
Sources: 27" iMac with 5K Retina display, 4GHz quad-core engine with 4.4GHz turbo boost, 3TB Fusion Drive, 16GB SDRAM, OSX Yosemite, PureMusic 3.01, Tidal & Qobuz lossless streaming, COS Engineering D1, AURALiC Vega, Aqua Hifi Formula, Fore Audio DAISy 1, Apple iPod Classic 160GB (AIFF), Astell& Kern AK100 modified by Red Wine Audio, Cambridge Audio iD100, Pro-Ject Dock Box S Digital, Pure i20, Questyle QP1R
Preamplifier: Nagra Jazz, Vinnie Rossi LIO w. AVC module, COS Engineering D1, Wyred4Sound STP-SE II, Nagra Classic Preamp [on review loan]
Power & integrated amplifiers: Pass Labs XA30.8; FirstWatt SIT1, F5, F6, F7; Crayon Audio CFA-1.2; Goldmund Job 225; Aura Note Premier; Wyred4Sound mINT; Nord Acoustics UP SE NC500MB monos; LinnenberG Liszt monos; Crayon CIA-1T [on review]; Audiozen Lysios [on review]
Loudspeakers: Audio Physic Codex; EnigmAcoustics Mythology 1; Boenicke Audio W5se; Zu Audio Druid V & Submission; German Physiks HRS-120; Eversound Essence
Cables: Complete loom of Zu Event; KingRex uArt, Zu and LightHarmonic LightSpeed double-header USB cables; Tombo Trøn S/PDIF; van den Hul AES/EBU; AudioQuest Diamond glass-fibre Toslink; Arkana Research XLR/RCA and speaker cables [on loan]; Sablon Audio Petit Corona power cords [on loan], Black Cat Cable redlevel Lupo
Power delivery: Vibex Granada/Alhambra on all components, 5m cords to amp/s + sub
Equipment rack: Artesania Audio Exoteryc double-wide 3-tier with optional glass shelves, Exoteryc Krion and glass amp stands [on loan]
Sundry accessories: Acoustic System resonators
Room: 4 x 6m with high gabled beam ceiling opening into 4 x 8m kitchen and 5 x 8m living room, hence no wall behind the listening chairs
Review component retail: €10'500/pr

Chancing upon a web
poster from their German distributor, I poked Zu bear Sean Casey for a full reveal. "A new Druid is imminent and will hit Munich 2017. No details yet. All that will happen at the show. These MkVI are a wood core with oriented carbon fibre. That makes them a fully composite/epoxy infusion build. As part of the layup I haven't yet made time for wood veneers. For now we're talking paint finishes. One feature you should like? They're about twenty pounds each lighter than your current MkV set. Makes moving them in and out less of a pain." I'd not seen that coming. I was as happy as a snorting pig with our resident ivory-skin Druid V. Looking at the strapping graphic, of a man's head hiding behind what seemed bigger than the Union model's existing coax, I wasn't sure that a higher-tech cab was the only reason for the rise of Sir Mark the Sixth. But, I'd have to sit pretty and wait for things to leak like Chinese water torture. Cue Hakeem Lyon's theme song from the Fox series Empire: "Drip, drop, drip drippety drop."

Having read how Zu teased a forthcoming flagship speaker at Denver, I entered 'Zu Experience' into the search engine to draw this up: "Have been in discussion with Sean who permitted release of some info. First, the front-firing 18" of the prototype will likely become twin 12" sidefiring subs, the widebanders likely to roll off at 35Hz. There will be built-in amplification but Zu recommend outboard sub amps. At present the 20wpc FirstWatt F7 seems to be amp of choice because Sean boosted efficiency of the subs to nearly approximate that of the widebanders. An outboard low-pass filter box will be provided for sub amps, using analog filters with greater range of adjustability than the current Definition 4. The paper drivers will have some tech at the bleeding edge for a massive increase in stiffness without any weight gain. Lastly, the cab will be maxed for stiffness with Ply plus resin-molded monocoque carbon-fibre impregnated multi coring..."

This suggested trickle-down tech from Experience to Druid cab; sensible when the new range topper replacing Dominance would likely be far too much speaker for most. Being offered a look at Druid VI to contrast against our V was a neat proposal. Having earlier in the year reviewed Vivid Audio's smallest Giya model, I'd been deeply impressed by their moulded glass-fibre enclosures with balsa cores. They seemed demonstrably quieter than traditional boxes. If Zu went partially composite, I ate an informed hunch for lunch. It'd be equally demonstrable. Yum!
Demonstrating the size of Zu's championed 20lbs Radian compression tweeter.

Zu's Utah neighbours Wilson Audio are famous for their ultra-hard bonded composite enclosures. For their top models, Wilson Benesch in the UK specialize in carbon-fibre cabs. Germany's Kaiser Acoustics champion tankwood, a resin-injected Plywood compressed to 60% its original thickness to become bulletproof. Mark & Daniel of Shanghai work in synthetic marble. Spain's Kroma Audio use their country's version of DuPont's Corian called Krion to chemically weld a box without any screws. Crystal Cable capitalize on a German equivalent for their Minissimo model. Æquo bond Plywood, synthetic thermo-formed stone and a secret compound called Grey Matter. The underlying theme is the same: hear less of the box, more of the music. The inside of a speaker is the by far loudest part of a room. It's common sense how playback with low bass played back more and more loud creates greater and greater stress on the enclosure. Shy of coming apart, its only avenue of protest is to talk back via vibrations. It's why ambitious speakers go after materials which are denser than the ubiquitous MDF. It's why Magico, YG Acoustics and Stenheim feel that aluminium is best whilst the Finns of Prime used natural stone and Waterfall and Perfect8 go for tempered glass.

Now Sean Casey had committed himself to pushing the Druid enclosure to stiffer mechanical specs by revisiting how it goes together and what materials it's made of. That this would entail a significant weight loss was brilliant. Who wants to reinforce their suspended flooring to indulge the hifi hobby? At this stage of the news drip, I imagined that locating carbon-fibre bits inside the box would sidestep having to finish them. It'd be easier and more cost-effective to dress outer Ply skins in gleaming lacquers—something Zu had perfected over many years—than getting carbon fibre to sparkle flawlessly, particularly when this wouldn't be an all-carbon affair marketed at trophy pricing. But I did suspect that the existing widebander would borrow from the Experience [early prototype with 18" woofer at left] and get an even deeper nanotech makeover than our V already had. Time to cue up Hakeem again.

By April 18th 2017, "debut is still Munich but your set is delayed. We are waiting on magnet material from China. First batch didn't make spec. Second batch in process but not sure how long it'll take." My inner sleuth flashed on rare-earth metals. Neodymium for the widebander? I then asked Sean whether he'd experimented with ceramic foams like Audio Physic exploit in a model I just reviewed. "I've played with or researched a fair bit all the major coring materials including the metal, ceramic and epoxy-based foams. They can be useful for manipulating air-particle motion and have their place in coring but within our designs don't really fit. Wood and cellulose still pack far greater strength-to-weight and fatigue advantages. They're second only to some steel alloys and carbon-based structures. We'll come back to this when I send over some drawings."