"A neodymium alloy caused the main holdup. Our ten-inch driver is mostly new but continues the ceramic magnet. The delay was on the Radian-based tweeter motor. The alloy diaphragm is Radian's from Orange County but we give it a secret nano-level blessing. That really improves the dome's behaviour and sound. Same basic story for the new paper-cored widebander. Flux density continues to be very high for both units. The material changes are mostly due to mounting and housing needs. This gets more apparent when you look over the drawings. They show the new housing. With it, we are truly working from the driver outward. All the stress and wave vectors of tension and compression move from there. Normally you build an enclosure to hold the driver. With Druid VI, we started with the driver as nexus and built out from there. The cross section shows carbon-loaded structural glass-fibre tubing damped with a wood core in the x, y, z corner positions as well as compression elements between driver and housing stresses. So what do wood, cotton, carbon and some steel alloys have in common? They all exhibit amazing fatigue curves. Wood/cellulose can also have exceptional damping qualities while simultaneously exhibiting near top-of-the-list ratios of strength to weight."

The exploded drawing below shows most of the mechanical assembly at left and the epoxy resin infusion on the Russian birch-core, then the layers of fiber, then the layers of firmer and clear coats on the right."

At HighEnd Munich 2017, I had a chance to catch up with Sean and presample the VI. It will not replace the V. It becomes a hotrod alternative. Given a 400% price increase on its hi-zoot drivers plus the cab's structural complications to double the retail price, that's sensible. Incidentally, the promised weight loss was temporary. Sean ultimately decided to stick with the massive aluminium plinth. That put the 20lbs savings right back on the scale. As to the profile of the new trim ring which actually is part of the enclosure, it's not for dispersion improvements as might be assumed. Sean simply wanted it to look as close as possible to the monolith in 2001: A Space Odyssey. Because a massive bolt with compression plate now torques the widebander into the baffle from the rear, the previous eight fixing bolts became superfluous. This makes for an even cleaner look. The tweeter horn obviously retains its four bolts.

Munich's dedicated 20Ω-happy amps were Audion's 2A3 monos, one of Sean's favourite valve Druid mates. On sonic improvements for the VI, he highlighted a superior transition to the Radian tweeter with overall greater speed, clarity, resolution and extension from an even quieter cab and tweaked drivers. Coincidentally, at Munich the Druid's structural makeover paralleled what Manfred Diestertich did for their brand-new Audio Physic Codex Structure described here. The obvious upshot is that the less box you mean to hear, the more the box must sonically stop to matter. To shut up final chatter beyond even the V, Sean went outside the usual predictive software like Comsol. Instead he teamed up with a researcher and facility to gain access into even more advanced modelling. Whilst minus small cosmetic changes the VI looks much like a V—a bit less so from the back—how it goes together structurally and with what materials palette are of a higher order.

Here's a collage from Polish contributor Dawid Gryzb's Munich show report for HifiKnights. German Zu and Spatial importer Mach One Classics had gone after a Route 66 theme. This and Sean's DJ skills plus his outside music choices made for a welcome break from the presentational slickness and audiophile pap that was common elsewhere. Whether I'll make deconstructed speed metal noise part of my musical diet is another matter entirely. For a 'delete and reset' reality check, Zu exhibits are simply sans pareil.

Incidentally, the new bore in the phase plug's centre has no geometric function other than hold a laser guide for easy toe-in verification during setup. If you're still wondering how an already compact ultra-shallow box like the Druid V's could audibly improve by becoming stiffer, remember that even a 98dB sensitive high-Ω driver like Zu's is really only 10% efficient by way of how much of its acoustic energy couples to the air. The rest disperses through the basket/enclosure and voice coil to make noise and heat. The more of those 90% can be removed from the mechanical feedback loop to become inaudible, the better the actual 10% will sound. An easy gauge for driver efficiency not sensitivity is motion. The more a driver moves, the less effectively it couples to the air and the more distortion it generates in the process. Under most conditions, Zu's hard-hung driver can't be seen to move at all. That's a very good thing.

By September 1st 2017, "we received and processed the second batch of tweeter magnets. Looking at our tests and measurements, we're good to go. We have a set burning in with your name on it. To ensure fidelity and long-term performance, we are going to pull them in after two weeks to remeasure, all in this batch in fact. Very likely there will be no issues. If they pass the two-week test, then they go back in for three more weeks of burn-in, to be sure they hit you sounding brilliant. Worth the wait? I believe they will be." By September 26th, "we have a nice batch of tweeters that passed the soak test and have been returned to the burn-in rig. As your set have the most time on them, I would like to use them for RMAF before swapping them back into your white cabs and getting them out." Of course I told Sean to put his best tweeters forward. Delays are part of the game. Pros manage them via emailed updates. What were two more weeks when Zu had been at the Druid for already 16 years?