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Looking for a precedent or parallel development to the Definitions elsewhere, I gravitated to the Triangle Magellan and Concerto, having owned Triangle Lyrr and Ventis XS models in the past. Both French flagship speakers use a proprietary paper-pulp, pleated-surround, phase-plugged T169V80 wide bandwidth driver. It's capable of covering 60Hz - 12kHz although its actual employ is deliberately curtailed to 350Hz - 3.5kHz. A horn-loaded super tweeter fills out the top. Efficiencies of 93dB and 94dB are higher than the norm. There's multiple paralleled woofers. And, there's even rear-firing drivers. Now for the differences. 24dB/octave crossovers. Claimed bass extension to only 35Hz, with a Magellan-specific subwoofer in the works. Price points well in excess of the Definition, especially noteworthy in the absence of true sub bass.
At less money, 101dB, 16Hz and no crossovers
over the majority of the audible spectrum, this -- admittedly somewhat arbitrary -- Yankee/Gallic juxtaposition might have you appreciate even more how the Definition (in what it's trying to achieve and how it goes about it) is a pretty unconventional design and unique approach. There's a very interesting German website by accredited engineer Charles Altmann called Mother of Tone. It talks about the loss of natural sound in HiFi and cheap musical instruments, including reasons for why paper as loudspeaker cone material may be vastly superior to the hi-tech Kevlar, Beryllium, diamond and Polypropylene variants that run rampant now and are seemingly so much more advanced. It strikes me as no coincidence that on both sides of the Atlantic, a fast and very dynamic sound finds itself implemented with "outdated" paper drivers whose firms went through the considerable trouble of designing such crustaceans in-house.


Perhaps new for the sake of newness often doesn't have merit outside of louder marketing cries? Banana pulp Fostex drivers, paper-coned Lowthers, paper-pulp Triangles and Zus. It takes no wet work to detect a common theme. That and higher efficiencies and wide bandwidth coverage. I'll say no more. My prior ownership of three pairs of Triangles and then the Zu Druids speaks plainly enough to how this concept -- when executed properly -- fits my personal listening requirements like a bespoke boot. Left, my latest pride, a pair of vintage but perfect San Antonio Lucchese boots found at the Pojoaque Santa Fe Indian flea market. Old needn't mean outdated or inferior. In fact, this pair is so well built, it'll last well beyond my lifetime with a bit of common-sense care. No magic other than superior craftsmanship, hand-selected materials, pride in a trade and time-honored techniques passed down from father to son. Come to think of it, that is magic, just not otherworldly. Would the Definitions shake equivalent bootie very much of this world? The Zu website promises greater ease and even better integration between full-rangers and tweeter over the Druid - plus a nearly purely resistive load to the amplifier and a bottom octave that's anything but shy.


I was additionally hoping for greater detail retrieval from the upper midrange on up. That's the one area where, compared to my Gallo Reference 3s for example, the Druid is good but not state-of-the-art. Curiously, its strengths are such that you'd never complain of any lack of detail. You would realize it in a head-to-head comparison but returning to the Druids, you'd immediately revert back to Zu mode listening - cohesiveness, tone, dynamics, timing and scale. If your listening priorities mirrored mine, you'd call those five qualities -- in no particular sequence here -- senior in importance to ultimate detail. However, as a statement product, the Definitions would have to "climb down the ladder" so to speak, pick up those lesser aspects as well and dredge them up toward the top rung so that you could call it not just a design that focused squarely on the essentials but one that did it all.
Beyond detail and bass, I anticipated that the Definitions would eclipse the Druid in other areas as well. However, once the Method sub gingerly fills in the Druid's incomplete bottom octave, there really isn't anything else one would wish for -- or imagine could be done so demonstrably better beyond bass and presence region detail -- as to seemingly warrant a price hike from $5,300 (Druids + Method) to $9,000. What exactly, pray tell, would the Definition bring to the party for those extra $3,700? In three words, the audiophile visual qualities which significantly enhance the live illusion. You're not just getting the message delivered. You're seeing the messengers in plain view dispatching it to you.


How so? First off, enjoying stereo bass to 16Hz loads a space more evenly and accounts for those out-of-phase ambient cues that get cancelled when the bass signal is summed to mono. Although it's common belief that bass especially below 40Hz is omnidirectional and entirely non-localizable, the explosion of scale that results from stereo infrasonics is uncanny especially in the depth domain of the soundstage. Now add sheer cone surface area and concomitant displacement of air. Things become plain huge. Mind you, a solo bassist will not assume unrealistic proportions as though blowing up into a grotesque caricature of the 10-foot jolly giant. However, he becomes so much more realistic in how the instrument plays the original venue. Linking the performer to the greater context of the space she's performing in becomes a very tacit expansion of scale. It's a qualitative gain. Unlike many American obsessions, bigger in this case is better beyond the shadow of a doubt.
Bass output was beyond prodigious at first. I experienced that quickly sinking feeling of great promise hitting the unmovable wall. Sean merely grinned and offered to turn down the internal amplifiers' amplitude response. It turns out that the subject of whether or not to offer a user-adjustable gain feature has been a contentious give'n'take between Sean and co-designer Adam
Decaria. One argument reasons that the more adjustments are offered, the higher the chances that ill-informed or inexperienced hands will dial in suboptimal results. More than one cook in the kitchen spoils the soup -- with the designer in this case being le chef -- and no patrons are allowed anywhere near the pots and pans.


The counter position argues that appropriate sub-bass amplitude response is an unpredictable function of room size, setup, listener preference and average listening levels. It becomes thus vital to remain user-adjustable. For the time being, adjustments are performed at the factory and none of the Definitions sold thus far have been returned with their users begging for less bass. Perhaps it's not considered a really manly request to make? Leave it to a German reviewer to stoop that low. Seriously though, I would like to see a perhaps recessed external screwdriver adjustment. Too much bass is far more damaging and distracting than too little. An external access could fix it to room and personal taste in a matter of seconds. And if you'se spends your nine Gs, you'se cool to mess things up beyond recognition if you insist. So much for my lobbying against the kitchen remaining off limits. And no crossover control is implied or necessary, just a single trim pot for relative bass output.
Once Sean [left] had adapted bass response to my tastes, the immovable wall vanished and my spirits soared. The wholesale increase in perceived weight and mass over the Druid/Method combo remained spectacular. Post-op decays and sustains simply lightened up to no longer overpower the balance vis-à-vis the initial attack. Sound now achieved a solidity and presence that simply cannot be accomplished without a true foundation on the bedrock of the lowest-most audible band. With the Definition, that foundation proved fulsome and truly massive when called for yet always articulate and never ponderous or droning. Bass prowess here extends its beneficial reign into midbass transient attacks which tighten up over the already formidable Druid. Percussive events in this band now salute as snappily as the very best of gruff drill sergeants. But the most surprising aspect -- considering I couldn' t figure out how it'd been done -- was the increase in presence region detail above 1KHz. Plain as day to hear, I failed to grasp that if the Druid suffered a soft blind spot in that area (a slight dip in amplitude response), how would doubling up the identical driver enhance visibility?


It turns out that the precise physical spacing of these two drivers accomplished what could be called intentional reinforcement (like capacitive coupling) or a mechanical narrow-band "reverse notch filter". Applying listening tests and test bench confirmation, the designers discovered that they could eliminate the minor mote in brother Druid's eye without incurring any unwanted side effects. The Definition thus adds the inner sight (the ability to discern very fine details) so prized by audiophiles in this transitional band where human hearing is so astonishingly acute. Where the Druid nails the live feel of a singer's presence, the Definition adds the audiophile visual effects to appeal to both the heart and the mind. (The Druid's special boon to budget-conscious music lovers is that it opts for the heart over the mind when limited to pick one over the other.)


Queried on specifics about the Definitions' innards, Sean explained that the frontal array is loaded into a sealed enclosure no taller than the actual driver spacing and just deep enough to clear the motors. This leaves the bottom front half of the enclosure to the rear-firing woofers which are thus housed in their own sealed sub enclosure, occupying the back half of the cabinet right down the middle and then half the lower frontal space in an L-shape. Crossed in at 24dB/octave at 40Hz, your main amp driving the Definition speaker system merely "sees" the frontal array as a nominal 6-ohm load which never exceeds 12 and reportedly is as gradual and non-erratic as a dream, making for a relaxed and mostly resistive amplifier load.
To optimize power transfer and damping factor for the internal amplifier, the four
woofers are run as two series pairs which are then paralleled. The tweeter crossover has been simplified over the Druid's 6-part network to a 3-part, essentially a single capacitor without any notch filtering required. Here is the most shocking aspect about the overall expansion of scale: viewing the Definitions face-on. It's déja vu all over again. You're looking at the Druids with one more driver each. The Definitions are of identical height, with barely broader shoulders - and their double depth filling out the entire plinth rather than only half remains entirely invisible from the listening seat (and rather inconspicuous from the side). It's like seeing your brother return from boot camp remembering the adolescent. He still looks like himself but his voice has dropped, the army has put more muscles on his frame and his bristling vitality just standing there has obviously peaked.


Clearly, the Definitions exceed the Druid/Method combo. They will go beyond even a double Method/Druid array with the following three-count advantage: sub-bass integration is more seamless; vocal-range resolution is superior; and the whole magic is packaged in two rather than four boxes (of which the subs would be two rather sizeable boxes). It's the old more-for-less appeal: more performance for less - except that less in this instance of comparison isn't money but floor space and visual clutter. True, the Definition does not look as fancy as a compound-angled affair gussied up in gleaming exotic woods. Its design genetics don't include leather-bound manuals, tuxedos or established cachet. Cachet in America that is. Zu has just passed its 5-year mark in business. This firm is doing an enviably brisk volume in Hong Kong, China and Japan. On the order of 20 reviews have published altogether in those markets, with Zu's products appearing on front covers more than once and occupying an entire floor right below Wilson Audio in one high-profile audio-only building. It's the brand's visibility in its own domestic market that thus far bears little relation to my own take on these fantastic products. Zu's fully established elsewhere and still emerging at home.
Sean next talked about his days at Kimber in charge of the Kimber Select division, helping launch Talon Audio and Wasatch Cable Works before spearheading Zu out of his garage workshop. From there, he seamlessly segued into an impromptu and heady riff on particle velocity/pressure
Physics, of internal combustion engine and loudspeaker flow models. He punned how most cable designs trace back to Tesla and Edison and declassified military developments. He grimaced when remembering remortgaging his house to generate project funding. He shared how they run a company on essentially word-of-mouth and customer service excellence, all the while reinvesting into engineering, production protocol, fit'n'finish and personnel. It became patently obvious that Zu is about real passion and out-of-the-box creativity disciplined by high-level Physics. The focus is on performance over trophy Hifi and a true appreciation for vintage research often long since forgotten because it occurred well prior to computer simulations and predictive modeling.

Should you have a hard time reconciling the above paragraph with the NRC measurement of the older Druid published by SoundStage!, Sean explained how the Canadians had forgotten two things: use the 14" square jig he had requested be placed under the Druid's floorfiring opening at the proper distance and adjust the microphone position to account for the tweeter kicking in above 12kHz. The lacking jig defeated the Griewe loading which apparently fired through a wire mesh instead. This devolved the box alignment into an open 4' pipe driven from one end to lose all output below ca. 100Hz. It made for a truly disturbing frequency response plot. If the Druid really sounded like that flawed graph, Zu would have never sold a single pair.


But unintentional mistakes do happen. So does disbelief by even trained engineers who rely on conventional models to argue that the Druid's small enclosure and its driver couldn't possibly produce 40Hz as claimed. Numerous owners know better without necessarily understanding the exact workings either. Naturally, no such ownership is required to know that the Definition's claim for 20Hz flat is not only likely but rather predictable. What wasn't predictable to me but somewhat dreaded? The quantity of said bass whose four Eminence woofers are operated below resonance just like BagEnd used to (but with zero DSP equalization in this case). Casey's gain adjustment made all the difference. Within minutes, I graduated from pronouncing the Definition bass-heavy, a little muddy and over-endowed to trading up from my Druid/Method trio to this overachieving pair.
Gershman's AvantGarde at the NRC
As I experiment further with various micro to medium-power amps to mate to the Zus, I'll pen a full follow-up on future listening adventures. For today, let me begin my summarization as follows: $9,000 is anything but chump change. An investment of this magnitude entitles you to not just a glimpse of the HighEnd but the full and undiluted Monty, eternal addiction (and satisfaction) implied and guaranteed. The Definitions deliver in a very big way. They are a statement product that arguably only cheats when considered from the Trophy HiFi perspective. There's nothing here to one-up about - no space-age chassis materials; no complex angles, facets and curvatures; no separated boxes; no exotic woods; no potted outboard networks, bi- or tri-ampability or any number of other apparently statement-worthy de rigeur ingredients. In fact, the Definition is a box, period - modestly proportioned for what it contains but a box nonetheless.


What's more, it's a self-powered box. That's nearly a no-no when it comes to the constitutionally sanctioned birth right of every hotblooded audiophile: "You may mix and match speakers and amplifiers at endless random" [Abraham Lincoln]. So yes, there are many far more expensive ways to achieve 16Hz stereo bass. For example, build a passive speaker and let your prospective customer sweat the details on what bespoke full-range amplifier to acquire that'll sound glorious in the midrange, wide open yet elegant in the treble, powerful and articulated like Hercules in the bass while retaining exceptional speed and dynamics. Conversely, there's simply no way to go the fully passive route and keep the doors open to micro- and low-power S.E.T., Tripath and chip amp devotees and simultaneously invite the massive Rogue Audio Zeus' 200 triode watts as well (one of Sean's all-time favorite amps on the Definitions and reputedly dead quiet too). The Definition is a clever hybrid. It's a passive design with an onboard narrow-band active subwoofer. For all but the bottom octave, your amplifier of choice will directly determine your personal voicing fancies. Even the low bass below it will derive its signal from your main amp and thus mirror its harmonic distortion and other sonic behaviors.

In automotive terms, the Definition performs like a drag strip racer, goes on ordinary unleaded and eschews the curvaceously fancified bodywork of vintage gentleman racers in favor of the naked engine look. It does accept high-octane fuel just the same but won't really go any faster unless you picked your fuel supplier unwisely. This is an audio machine built by enthusiasts for enthusiasts. No corporate sponsorship, no Pepsi Cola commercials. What's exciting is that you can drive this beast with a superior but very affordable amp like the $850 6-watt Decware Zen Taboo. The FirstWatt F2 is a perfect match if you have $2,000 and prefer the reliability and MIA noisefloor of single-ended transistors. I expect that the $1,200 AudioSector Patek at 50 watts will be a real cherry too but details on that encounter are as yet forthcoming. Still, you get the idea. In the context of the Zu Cable Definition, statement means substance without bling, domestic practicality and a very unusual solution for the 5-watt crowd who loves string quartets and Pavarotti at full tilt as much as grungy Power Rock and the occasional drum kit whacking away from 5', i.e. at realistic levels without compression.


[As a nominal 6-ohm load into a transformer-coupled tube amp with a fixed impedance tap like my Decware Zen Taboo, the Definition puts out significantly more amplitude than the Druid. The amplifier/speaker impedance interface and thus power transfer of the Definition is far more in line with conventions than the Druid. While its measured 1w/dB sensitivity is in fact identical to the Druid, with the Decware it creates a ca. 5dB acoustical output advantage, readily obvious when looking at the volume setting of the preamp for matched levels (11:00 o'clock on the Definitions versus 2:30 on the Druids). The reverse would be the case into OTLs which increase their output into higher impedances and would express an optimized power transfer into 16 ohms rather than 8 or 4. Paralleling drivers doubles their acoustic output but halves their load impedance. It is this change in impedance and how the driving amplifier reacts to it that can be somewhat unpredictable. In this case, the 6-ohm load into a transformer-coupled tube amp (itself optimized, presumably, for between 4 and 8 ohms), creates the 3dB acoustic gain advantage of driver doubling if not more.]
Another way to classify the Definitions is to call them speakers for horn lovers who don't really want horns for reasons of size, expense and cosmetics. You get horn-type speed and dynamics, superior bass (unless your horns were Avantgarde BassHorns) and the same type of often startling realism. Imaging is arguably superior even. All in all, a tremendous list of assets and not a single true liability (the lack of user-adjustable bass gain is addressable for now at the factory). As Sean's visit drew to a close, I asked him to take my Druids and the Method sub back to Ogden and bill me for the balance. The Definitions are my new big-rig speakers. In my mind and to my ears, their surcharge is fully justified and in fact surprisingly modest for what you're getting. It's the soul of the Druid (which I called a spectacularly unspectacular speaker from the usual audiophile perspective) wedded to linear hi-rez across the band
and the kind of hyper-spacious soundstaging that relies on phase coherence, proper timing and fully realized infrasonics. For the manly men amongst us 'philes, you simply won't believe what well-damped cone surface does for the bass if its presence on your recordings is deliberately prominent and Stygian. This produces mindboggling scale of soundstage presence, with the tight tracking of peak dynamics seemingly well outside predictable applications and thus reason.

It goes without saying that the Definition is like a fish in water with Rock, gladiators and Shostakovich warhorses. Can it do subtle, however? With a vengeance. That's where the fast response times and limited excursions of high-efficiencies coupled to paralleled drivers justify their existence. Low-level retrieval is excellent even at background listening levels and completely oblivious to programmatic choices. New Age fluff, electronica, female vocalists, acapella funk romps and chamber music ensembles are simply differently styled forms of raw signal. The Definitions don't care. They simply latch onto whatever they're fed, at any volume you choose and over the entire audible band without prejudice. And just like the Druids, they do so with tone and density in a fashion that goes well beyond what the equivalently priced Analysis Audio Epsilon planar-magnetic ribbon speakers from Greece are capable of. As I said earlier, the Definitions are true statement loudspeakers. They simply look a bit butch but the $1,500 anything-goes lacquer option (adding 40 hours to the production process) can gussy up the finish to compete with Wilson Audio, Gershman Acoustics and other companies known for their immaculate custom lacquers. More definitive Definition stuff to come as my system settles in around my new amps and any other surprises that might come through here and gel in a special way with these Zus.
It's become nearly axiomatic to consider a reviewer's purchase the highest compliment possible for any product submitted for review. Naturally, personal taste remains the final arbiter. Over the years, I've made it pretty clear what moves me sonically and what doesn't as much or not at all. If my writings suggest to you that our aural preferences and values overlap -- and if you're in the market for a pair of reference speakers -- the Definitions truly are an all-out assault at the high-efficiency non-horned speaker craft, from a company presently far more recognized and supported in the Far East than domestically. Perhaps Corey Greenberg's infamous "old goat" statement applies when faced with a design & manufacturing gang comprised of hard-working mid-30s dudes whose engineering chops and conceptual ingenuity hide behind a facade of youthfulness, vitality and a stark refusal to kowtow to conventions? If there's an anti-mainstream movement afoot in audio, Zu's definitely part of it. It is my special pleasure in 2005 to give this sector of the market some well-deserved -- and overdue -- exposure in the little niche of the audio press served by our site. US-grown innovation remains alive as does value engineering, all right here on our own soil with Zu Cable's stubborn made-in-America approach. That's worthy of a standing ovation. What's more, the sonic results certainly beg for it outright.
P.S. 8/17/05: I've just been informed that as of today, all Definitions will ship with a user-accessible external bass amplitude control. As I'll get my personal pair modified accordingly, I will document this welcome new feature in a follow-up report. Kudos to Zu for listening! This now removes my solitary complaint about this very clever design. Bravo.
Manufacturer's website