- Written by Chris Groppi
- Published on 02 October 2008
Zu uses a proprietary acoustical modeling technique, called ZuRG , to design their speakers. The Druid is equipped with Zu-manufactured and designed drivers, including a wideband 10" driver and a composite dome super tweeter with machined aluminum horn radiator. The wideband driver covers 35 Hz to 12 kHz. The super-tweeter covers only 12 kHz and up. The wideband driver is crossoverless, while the supertweeter uses a simple high pass network. Like my Gallo Reference 3.1's, crossovers and their accompanying phase and time domain errors, are kept to a minimum. The cabinet is ported on the bottom, so the speaker's height above the floor (set by the feet) is relatively important. The cabinet porting is neither an acoustical waveguide nor a traditional port, and is one of the tricks of the ZuRG modeling. Impedance is a very easy to drive 12 Ohms, with an extremely high sensitivity of 101 dB per Watt per meter.
Internal wiring is Zu-made silver alloy B3 wire. The cabinet is MDF core wrapped in a composite skin. Combined with automotive paint, in standard or custom colors, the finish is just about perfect. Sean Casey of Zu apologized, saying the speakers had been used many times as a demo pair, leaving the finish less than perfect. I don't know what he was talking about. The Druids were the best-finished loudspeaker I have ever reviewed, and are up there with the best finished I have ever seen. Mine were finished in a rich, attention getting red, with a silver base and Zu logo. The binding posts were also the best I have ever had the pleasure of using. These patented Cardas binding posts have OFHC copper pins are mounted in a high quality plastic housing. A clamp, secured with a single large wheel holds the spades against the copper pins. These are really optimized for spades. Other terminations can be used, but they need to be kludged in a bit. Every part of the Zu speakers, from the cabinet finish to the binding posts to the drivers exuded quality. It is clear just from looking at them that the $3,400 asking price is a great deal. Three non-standard paint colors run an extra $600, and a black anodized tweeter, driver trim or phase plug run a few extra dollars each. If you want Zu to paint to any custom color, they will, but pricing is provided on demand.
Speaker mass is a moderate 65 lbs. The only design element I could find to poke at a bit was some cabinet resonance. Tapping on the front or rear baffle did result in a bit more ringing that you might expect. While the cabinet might be plenty stiff, it was not particularly inert. Some manufacturers use the flexibility of the cabinet as a part of the acoustical suspension of the drivers, so I have no idea if the "liveness" of the cabinet helps or hinders the performance. Really it's irrelevant as long as the speakers deliver the sonic goods.
The Druids came packaged one per box, with high quality foam packaging. Each speaker came with both spikes and hard floor feet, and a micro-fiber polishing cloth. The speakers come coated with a thick layer of automotive wax, which has to be buffed off by the user. This guarantees the highest quality finish, but does require 15-20 minutes of elbow grease per speaker. The result is well worth the effort!
What the buffing does cost in effort, Zu gives back many times over in break-in time. Each speaker is broken-in at the factory for 160 hours (almost a full week, 24 hours a day) using a Zu-developed technique. This means the speakers are ready to go right out of the box. No need for weeks of break-in, and wondering of you made a huge mistake waiting for the speakers to begin to perform.
I located the Druids in my room approximately where my Gallo 3.1's live. My room, as a day-to-day family room, has limitations that prevent me from placing speakers anywhere. I have little issue with this, as very, very few audiophiles have the luxury of a single purpose listening room they can set up in an arbitrary way. I toed in the speakers directly at the listener as recommended by Zu. The speakers were powered by my 200 WPC Emotiva RPA-1 amplifier using Wireworld Eclipse speaker cable with spade terminations. Zu recommends using a CD case to set the cabinet to carpet gap, which I did.