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The plan was simple. Like my brother-in-law Phil. But unlike Phil, this plan just might work*.
"Based on CES comments, we have made a few improvements to the externals, internals and the FRD and ribbon. As we have only shipped samples out to you and a few to Europe, we feel we should make the changes now before formal production commences. The early pair you have is good enough for sonic impressions, maybe even to base a simple review on but I think it's worth considering the Essence in preview mode until you get your personal pair of production Essence."

How you judge anything in life depends on what you compare it to. Enthusiasm on top of Mt. St. Helens will get tempered relative to the panorama from Mount Everest. But St. Helens is still pretty spectacular in its own right. If one never leaves Skamania County in Washington State, it's as high as it gets. Coming off my four-times-plus priced Acoustic System International Tango R speakers created the higher ground necessary to critique the first Essence pair. Judging it in its respective price class found it a much perfected Druid Mk IV which remained true to Zu's meaty signature sound but added a few vital new wrinkles.

* This and other bold quotes are from a collection of winning phrases from an annual collection of analogies and metaphors found by English teachers across the country in high-school essays. Thanks to regular reader Russell Dawkins for submitting a loaded list.

The unfair comparison demonstrated what the Essence cannot do - and which, to varying degrees, extends also to other speakers whence I consider the Tango R an ultimate reference in that regard*. With Zu, it's intricately linked to their 10.3" widebander. It creates innate warmth. Regardless of auxiliary tweeter, formerly horn-loaded, now ribbon, the big boy dominates. It's meant to as the very high 10kHz tweeter hi-pass with its shallow 1st-order slope prove. The Essence thus is no ribbon speaker per se. It's a speaker with a ribbon that's been deliberately weighted down by broad overlap from the whizzer [see right]. This, very good, makes for both seamless continuity and textural coherence plus broader off-axis response for a wider sweet spot. The shadow side of it pads down subjective top-end speed. With it, the delivery of true
tone is compromised. That, after all, relies on harmonic fidelity, i.e. a tweeter's ability to track the overtone spiderwebs of voices and instruments with their endless modulations as a function of finger pressure, air speed, bowing force and all manner of interpretative playing/vocalizing techniques.

*Whenever a reviewer tags any personal audio possession with the reference moniker, it's fair to also know what other reputable listeners think. Franck Tchang, designer of my speakers, forwarded the following e-mail from Shunyata Research: "We have received and set up the speakers. We burned them in over about five days. Caelin has reviewed the speakers. It is his opinion that you possess great genius, that never has he heard any speaker that even approaches yours and that it is a crime that you are not recognized the world over for your accomplishment. We are still in the midst of growing accustomed to the remarkable nature of your speakers." - Mino Christante, Shunyata Research

The tone density of the Essence is too heavy and its tonal center too low to deliver the complete inner lightness -- in both meanings of non-heavy and brilliant -- of true tone. By true tone, I mean the full wealth of complex ephemeral stuff above the fleshy fundamental and low harmonics. While (no surprise there) the triple eight-inchers of the Tango R extend lower with more heft than the Essence, it's (surprise!) the latter's tonal center which actually sits lower. That's due to its top end being less illuminated and finessed than the Tango's Esotar clone which combines with the copper, gold and Platinum resonators built into the French speaker.

The tone of the Essence is similar to 'generic' tube-amp tone. It stems from warmth and texture -- others might call it colorations -- and not fully elucidating the finest upper harmonics. Coming off the Tango R precedent, this translates as:

Diminished harmonic haloes around tones
Shorter decays
Less hall sound and recorded ambiance
Less image focus, separation and, particularly on superb recordings, less soundstage depth
Less tone modulation sophistication and, with it, a lower level of perceived microdynamic life than the lower-efficiency speaker in this instance

Her vocabulary was as bad as, like, whatever. Consequently, something about the sound compacts. Call it density and we're back at using a large-diameter driver to handle the critical vocal band. The ribbon adds the formerly missing extension and makes for a more continuous radiation pattern in the hand-over range which serves coherence. But it does not fundamentally alter the signature sound. The only way Zu could fully liberate the upper harmonics would be with a far steeper, much lower ribbon crossover point, say 4th-order and 1kHz. But then that telltale and so agreeable fleshiness of Zu's sound would most likely suffer a cold infusion. The whole of-a-piece continuity of the concept would likely sink like...

The little boat gently drifted across the pond exactly like a bowling ball wouldn't. Seamlessly integrating a ribbon tweeter with a 10.3" widebander seems predicated upon Zu's particular choices here. They mix whizzer and ribbon action over multiple octaves to hide the seam and extend a meatier mien into the upper ranges. It gives more quantity of extension and dispersion but the innate quality remains. To a more pronounced extent, the same happens at the other end. Despite its acute simplicity of execution, that foam pyramid really does the promised business. Shy of perhaps half an octave (meaning irrelevant on most music), the bass reach of the Essence tracks that of my reference speaker. While displacement and ultimate amplitude are naturally second, this has a very practical upside. Essence bass involves the room less. It doesn't assault with an overly ambitious artillery of attack weaponry which needs to be carefully integrated with acoustic tuning tools. Good low in-room bass is a far from simple pursuit. The Essence makes it a lot simpler (and cheaper) than my expensive boxes.

Even in his last years, Granddad had a mind like a steel trap. Only it had been left out so long to rust shut. Not ringy and underdamped like a ported alignment; not as dry, popping and overdamped as a sealed box; the gentle compression/slot loading of Zu's solution makes for a quick, intelligible yet semi-buxom bass that goes a lot lower than the Druid when recorded. There's no gratuitous tag-on, just a downshift of the attenuation point. This comes to the fore particularly on synth-enhanced material which sounds threadbare if the 30-something region is missing in action. Those armed forces have now returned home.

It was an American tradition like fathers chasing kids around with power tools. For other traditions, think comic book movies. To borrow from Spiderman, the Essence could easily strike you as your friendly neighborhood slugger. That's because in matters of loudness stability, this speaker is about as imperturbable as they come shy of going really big and expensive. Nothing tips or shifts. Things simply get louder and louder. And louder. If there's a limit (there always is), it's well beyond neighborly civility or proper respect for one's hearing. As such, it's perhaps not the most practical of assets -- hopefully never exploited fully -- but for any spirited jam sessions, this speaker is Peter Gabriel's hammer. Forget subwoofers. They're not needed.

Alas, the Essence likes more power than its membership in Club Hi-Eff would suggest. 8 watts of Yamamoto-class 300B fuel are plenty sufficient in matters of sound pressure but if you wish to underpaint the warmth aspect and emphasize the inner slugger, go with something more potent. For tubes, I'd be thinking Octave, Rogue, Manley or the new WLM line. That's because to do single-ended right will cost you to avoid going softer than necessary.

He fell for her like his heart was a mob informant and she was the East River. The intermediary take on the Essence was as a seasoned Druid with clearly more potent bass extension and weight; more resolving power on high; a wider sweet spot; and a more seamless integration of drive units. Then my personal pair of the first formal production batch arrived [below].
Soft-headed stubby spikes were preinstalled in the lacquered silver plinth. Those blunt footers are ideal for wood, tile and other scratch-prone surfaces. Sharp long spikes are included for carpets. Further stock items are tack cloth, copper cleaner and grills. For the latter, black is standard, clear anodized silver optional.

"Your pair had about 120 hours of good hard play by which time they usually open up. We know that cold air during transit particularly by plane causes our FRD to get inhibited. It takes about a week to get back in the mood. Effects of air freight on the ribbon tweeter are still unknown. Also, there is plenty of Teflon in the capacitor lead-ins which benefit from further break-in. We pulled your pair from a production run that is still playing and we're shooting for 250 hours on those before they leave."

This explained the rather hooded and opaque mood in which my pair arrived. To back up how Zu can hit its 0.1% tolerance window for the drivers, Sean Casey had submitted a 14-page procedural paper for internal use which still didn't include cabinetry, final QC and packaging. He also included actual free-air measurements for the drivers of my pair. This indeed showed them to be the proverbial identical twins. Time to put the pedal to the metal.