August 2013
 

Zu Audio Union Loudspeaker
Outstanding transparency and uncompressed dynamics.
Review By Rick Becker

  Young riders dressed in dark clothing dart about the urban industrial landscape on 883's and Forty Eight Sportsters in a Harley Davidson promotional video. My mind pans left into the Zu website where black and white photos of young dudes click in and out; segue to a video of the making of a speaker in their dusty shops. Of course Zu Audio Union speaker is there and noticed it only cost $3000 for what appeared to be quite an impressive speaker. Looking back at the pics, at least the guy in the spray booth wears a mask to protect his lungs. Both Harley and Zu Audio are fiercely American, one an elderly icon and the other just a teenager. Both keenly focused on what they are doing and insistent on doing it their way with their own vision of moving forward while seeking to recapture the thrill and excitement of the past. Music used to be more central to our culture, more fun, and Zu is using modern technology to bring that past into the present.

I'm old enough to be the father of most of these guys. Maybe that's why my first attempts to get review samples of their speakers didn't work out. Nor were my encounters with their rooms at shows always exhilarating. But sometimes they were and it was clear they were into something unique. Having been that young once, I understood the meaning of 101dB/W/m efficiency. Not once, but twice Altec Voice of the Theaters dominated my living room, only to be given up because I was damaging my ears driving them too loud with 1970's vintage Pioneer solid state gear. Motorcyclist, head banger; been there, done that. A large painting of me standing on the salt flats in Utah, reminiscent of the cover of John Lee Hooker's Endless Boogie (1971), each a legacy from my first marriage, hangs in the family room. Decades later I discovered the High End and low powered tube gear. I could hardly believe there was that much music hidden in the grooves.

It was the six watt per channel Triode Lab EL84TT integrated amplifier that led me back to Zu Audio once again. As fate would have it, they had just announced the new Zu Audio Union speaker with coaxial super-tweeter and a 10" full range driver. After a delicate exchange of emails they made a commitment, but production delays put off the arrival until right before the Montreal show. Three weeks of writing the show report, followed by the furniture trade show, followed by the writing of the Triode Lab review and finally the Unions were very nicely broken in.

The Set Up
I started with the Zu Audio Union speakers in my usual speaker position which had served most of the speakers I've reviewed quite well. This didn't work, so I angled them in toward the listening chair slightly which brought the midrange more forward and strengthened the treble. But the soundstage seldom extended wider than the speakers in this configuration. Ultimately, I found greatest satisfaction by bringing the speakers closer together than normal by about 6" total, and aiming them straight ahead. The Unions were not as wide dispersion as most of the speakers I've reviewed. Since my side walls are far to the left and right of each speaker, I typically experience very wide and deep soundscapes. Here I achieved a reasonably wide soundscape with the Zu and the EL84TT, allowing me to make more definitive evaluations of the Triode Lab amp. One evening, when I surrendered the listening chair to my friend Tom and sat in the recliner to his right, the soundscape immediately collapsed. The music continued to come forth with all its dynamics and clarity from the speaker directly in front of me, but it felt an awful lot like mono. In the centered listening chair I was free to adjust my posture without negatively impacting the stereo imaging and at no time did I feel like my head had to be held by the proverbial vice. But people off to the side will not experience the soundscape that many audiophiles prize…at least not with this amp.

What A Difference 99dB/W/m Efficiency Makes!
The first watt of any amplifier is the most important one and this is especially true when the efficiency of the speaker is 99dB/W/m because the first watt will be playing almost all of your music in typical listening rooms. The six watts of the Triode Lab EL84TT is more than sufficient to drive the exceptionally easy load of the Zu Union. As Carl at Triode Lab told me, some  of their amplifier customers with Zu speakers prefer their 2A3 power amplifier (3.5 watts per channel) to 300B amps (typically 8 wpc) or EL34 amps with considerably more power. My listening room is about 6000 cubic feet with an open doorway to the kitchen and a large opening into the family room, so the room itself is well ported. I did not want for more than six watts from the Triode Lab amp. Nonetheless, I also drove the Union with three other amps: my slightly tweaked Manley Mahi monoblocks (13 wpc in triode, 20 wpc in ultralinear), the new Coincident Turbo 845SE integrated amplifier (28 watts per channel with 845 tubes driven by a 300B) and my reference Tube Magic M23SE Mk3 monoblocks (18 Watts per channel from parallel 300B tubes). From a power standpoint all the latter amps were overkill, but the revealing nature of the Unions allowed the differences of the amplifiers to come through. With the volume control in the 12 o'clock position with the 6 wpc Triode Lab peaks would reach 100-102 dB at the listening position about 8 feet from the drivers. That same amp had an improved sonic signature when two NOS HIT-Ray (Panasonic) EL84 tubes were mated with two of the Electro-Harmonix EL84. The Zu revealed stronger bass, more tonal coloration and three-dimensionality and greater micro and macro dynamics with the two HIT-Ray tubes. The Coincident amp revealed even greater sonic richness as you would expect from an amp that cost more than twice as much as the Triode Lab.

What you need to read into this is that the Zu are very revealing of the amplification with which they are paired. This doesn't mean you have to have the newest, most expensive gear to achieve a rewarding musical listening experience. My vintage solid state Tandberg 3012A integrated amp with 100 wpc, much of it biased into Class A, sounded very nice with it during the break-in period. The music was warm and inviting, if not the last word in resolution and soundstaging. The Triode Lab with the EL84 tubes was tight from bottom to top, revealing a slight upward tilt on the treble. That it became irritating over time turned out to be due to a slowly failing EL84 tube, a situation that was corrected with a matched pair of new tubes.  It was also a very transparent amplifier with a high degree of focus.  The Coincident amp was similar providing a fuller sound and it also brought down the prominence of the super tweeter to a more comfortable level.

Can You Hear Me NOW?!!!
Not only does the Union get loud real quick when you turn the knob, it is immediately evident that they are extremely transparent — as if your old speakers were wearing sunglasses by comparison. It also gives you impressive focus — if the rest of your rig can pass that on down. In fact, installing the Union was not unlike having my cataracts removed when the world suddenly got brighter and I went from being very near-sighted to having 20/20 vision. Not only is the lead singer in focus, but the back-up singers at the very back of the stage are now clearly audible for me. It is as if there is a lot more light on the stage that allows you to see and hear every musician and instrument. And if you also get the speaker positioning in the room correct, you will have pretty close to pinpoint imaging. But mess up the signal with an inferior cartridge or DAC and you will only get out what you've put in. Not that it will be horrible, but the quality of your rig will have to rise to a very high level to surpass the ability of these speakers. This means that you can start with these moderately priced speakers and upgrade with whatever tube or solid state gear you fancy over the next decade or two before you feel compelled to swap out the Unions. You can't say that about a lot of speakers out there — most of them will limit your choice of amplifier at the very least. Many people try and fix a problem with new speakers when what really needs improvement is the gear upstream.

The other most obvious characteristic of the Union is their dynamic capability. Take a rim shot or pluck an electric guitar string with a pick. They've got attack. Even pianos have balls when played with ferocity. Xylophones? Not so much. Combine high efficiency with outstanding attack and you should have outstanding dynamic range. And you do, once you get the volume up into the broad sweet spot with musical peaks reaching the 85 to 100 dB range. Lower the volume to late night listening levels and the dynamic range obviously compresses as it does with most dynamic speakers. But hey, you know where the fun is. And the decay? It must be just about right because it didn't come to my attention as being too short or too long. And as I've learned from Paul McGowan's blog, it is the attack that determines the timbre of the note and the Union gets it very, very right. For the most part I would say the Union is capable of excellent tonal coloration if you've got an amplifier that can do it justice. For the one exception I have to rely upon my friend Tom who listens to a lot of classical music. He noted some congestion in the treble with demanding orchestral music, particularly with high violin notes. If large scale classical music is a major item on your menu, you might want to check this out before committing. I had no problem with rock, jazz or electronic music in this regard, except with the prominence of the treble when using the Triode Lab EL84TT with its extended high frequency response. Even string quartet sounded great, until the violins went for the high notes where they sounded a bit like they had steel strings, but only in a narrow high frequency window. Since most tube amps roll off the high end slightly, this should not be a problem. If you have an amp that is bright on top, you may want to pay attention to the output of the super-tweeter.

The 10" full range driver is the principal feature of the Union. It is good for 45 Hz to 12 kHz and like the full range (or nearly so) drivers of some other outstanding speakers, it is powered directly by the amplifier without a crossover. The transparency of such crossover-less designs is usually outstanding, and the Zu Union is the most transparent of all that I can recall from memory. This driver is able to resolve midrange lyrics that escape most other loudspeakers with dynamic drivers regardless of price. Other designers have implemented nearly full-range designs by pushing the woofer down to around 200Hz and below and the tweeter up above 7-8 kHz with great success, but Zu has stretched the envelope even further with the Union. And to create a point-source design, they have mounted the super tweeter concentrically with the 10" driver, rather than mounting it on the baffle as they have done with the lower-price Omen or their higher price models (other than the Soul). The result is a coherency that is conspicuous only by virtue of the frequency limitations of the driver itself.

The bass goes down to 45 Hz and it is tight, tuneful and transparent all the way there. But what makes it better than most is that it falls off quickly with grace, not groping for another few Hz and muddying the bass by trying to be more than it is. This bodes well for those of you who feel compelled to add subwoofers as you can continue to run the Union full range and bring the sub in at a low level. Apartment dwellers and those with children who go to sleep early will probably be perfectly happy with the Union just the way it is. As I looked at the frequency response graph on their website, I was puzzled by the bass extension below 40 Hz which did not correlate with what I was hearing. Sean Casey, the main man at Zu, explained to me that they take their measurements "in room" and that lower hump in bass response represents room reinforced response. I was probably not getting this result because in my positioning, the front baffle was 64" from the wall behind it and since it is on a very long wall, there are no meaningful corners to reinforce the bass. In a smaller room with real corners, you will quite likely experience more mid-bass response than I did.

Subwoofers To The Rescue?
Bass addicts should be warned that you will need quality subwoofers to match the speed and clarity of the Union. The Zu Undertone at $2500 is a downward firing acoustic suspension subwoofer that would take only a small leap of faith to purchase, given what I've heard from the Union. True bass-heads will want two of these to really bring out the ambient room tone of live recordings, which brings the system price up into the $8000 range — a point where you might want to consider a pair of larger Zu speakers. Separate subwoofers, however, will allow for optimum placement for bass reproduction that would otherwise be compromised by using larger full-range speakers. A single sub will get you music deep down, but a pair will more likely give you a sense of being in the same room as the musicians. You get to choose, of course, but don't think you can get by with a cheap subwoofer.

I resurrected a pair of prototype Tekton Design subs with concentric 11" drivers — the rear driver in a sealed box, the front driver mounted on an extended open baffle in free air. They are driven by an internal 200 watt BASH amplifier and the signal was delivered from the speaker terminals of the Coincident Turbo 845SE integrated amplifier (review forthcoming). The initial result was quite disappointing until I added Boston Audio TunePlates beneath the spikes of the subwoofer. The TunePlates tightened up the focus of the subs, whose spikes were not sharp enough to penetrate the carpet and dig into the flake board below. This brought the speed and clarity of the subs fairly close to the Unions and I was able to cross over nicely at 50 Hz with the subs placed just outside the Unions. While the Unions were really good without the subs, I felt there was a slight upward tilt to their frequency response. In reality, it was just the absence of lower bass to balance out the high extension of the super tweeter. Had the super tweeter been rolled off around 15 kHz, I probably wouldn't have had the perception of an elevated high end. And if you are in a room with real corners, and the Unions are placed a little closer to the front wall to take advantage of the room reinforcement of the bass, you will probably be just fine with the Union alone. But man, it was really sweet to have the full-range extension afforded by the subs. When I added the subs it shifted my attention more squarely on the midrange and I had little or no quibbles with the treble. The downside was the additional clutter of two big boxes with their attendant power and speaker cables that made it more awkward to load the CDs and LPs in my rig. The trade-offs in life never cease.

Another point that needs emphasis is that with the high efficiency of the Zu Union speaker, you will get great bass even with low powered SET amplifiers. The EL84 tubes of the 6 wpc Triode Lab EL84TT integrated amp I recently reviewed are very tight and resolving at the frequency extremes. The more costly Coincident Turbo 845SE integrated and the Tube Magic monoblocks (which use 300B tubes) had a fuller sound that gave added majesty to the mid-bass. You need a high quality amp to get the very best out of the Union, but not a high powered one. The speakers will let you know when you've got the right amp (as well as everything else upstream).

Bass Technology/ZuGriewe
There was a lot written about the ZuGriewe technology on the website but it still didn't make a lot of sense to me so I called Sean for clarification. He explained that the ZuGriewe system was really a combination of several different approaches to internal resonance damping. Ron Griewe, a former editor of Cycle World magazine and motorcycle guru inspired Sean to incorporate some of Ron's ideas into speaker design. The Zu are ported out the bottom of the cabinet through four slots running almost from spike to spike near the outer edge of the cabinet. Each slot is tapered from 0.5" at one end to 0.25" at the other. Inside, at the top, around the driver is wrapped a thick layer of what looked like loosely packed felt. Down the center of the cabinet sits a pyramid shaped tower of polyurethane open cell foam. The theory being that, like a motorcycle muffler, the acoustic energy travels down the center of the enclosure and this is where you want to place your absorptive material to reduce the energy within, not on the side panels. The foam converts the sound to heat and very little acoustic energy escapes through the slots at the bottom though I noticed greater vibration at the bottom edges of the cabinet than on the sides.

The result is that the back side of the speaker cone sees very little internal noise and consequently, almost all of the musical energy radiates forward from the outer face of the driver, unlike with most other ported systems where the bass is augmented by music coming from the port at a slight time delay. Furthermore, the porting system of the ZuGriewe system is tuned over a larger frequency range than typical speaker ports which operate over an octave or less. It also increases the efficiency of the bass — a claim that is verified by the excellent results achieved with even very low powered tube amplification.

What It Sounds Like
To this point I had been using amplifiers that were also in house for review, hence changing two components at the same time. There is a reason reviewers have a reference system and ultimately I returned to my reference set up that included the world class Coincident Statement preamp and the more obscure but equally outstanding Tube Magic monoblocks. I really wasn't prepared for the results, since I had found greater transparency and focus with the Triode Lab EL84TT integrated and even more so with the Coincident Turbo 845SE integrated than what my reference system was capable of giving me up until this time. The inclusion of the M23SE MK3 monoblocks with their parallel 300B design putting out 18 watts per channel propelled the Zu Unions up yet another level. The music became even smoother and the soundscape more precisely defined and more frequently it broadened beyond the width of the speakers. The super tweeter became even better integrated into the full range driver, losing the upward tilt altogether. But I have to restrain myself from going all out with superlatives because good as it was, it still gave up the music and room tone that lies below the 40 to 45 Hz level. The dynamics and transparency — the two outstanding features of the Union — did not change so much from the other amps, but with the increase in focus and more holographic imaging combined with the increase in smoothness and tonal accuracy it made it easier to believe you were listening to real musicians in real space.

It was a Friday night at this point coming up on midnight, but I summoned enough energy to hook up the Tekton subs in preparation for Tom coming over the next night. I dared not listen to a single song, fearing what I knew would happen since Saturday is an important day at work. It's always fun when Tom comes over because he brings with him a different palate of music that gives me fresh insight beyond what my own reference music affords. We started out with his compilation CD with stuff like Tower of Power's "Diggin on James Brown", some Tito Puente, Jennifer Warnes singing Leonard Cohen's "First We Take Manhattan", Clifford Jordan from Live at Ethel's on Mapleshade, one of Todd Garfunkel's recordings of new tango music from the group Sera una Noche, and moved on to some LPs including Sonny Rollins' Way Out West and from Count Basie,  88 Basie Street as well as a direct-to-disc LP and some classical stuff. I also dug up some really clean live recordings from the American Folk Blues Festival '70, some Chinese drum music from Yim Hok-Man, and from John Marks' Glass Bead Game a string quartet piece from Zoltan Kodaly and from his Pipes Rhode Island CD, Howell's "Master Talllis's Testament" with some monstrously low organ notes that sounded as real as the organ recital I attended recently at my 45^th college reunion.

We were all over the map. And we both loved what we heard, save for Tom's apprehension about their suitability for classical music. He regularly attends concerts with the Rochester Philharmonic Orchestra (12^th row, center), whereas for me, that is a rare occasion. Adding the subs brought the system to full range by anybody's standard although I have heard much more expensive subwoofers that might provide more subtlety in the lowest bass. Quantity was not an issue here. The subs brought the tonal balance to even keel allowing the music to supersede the equipment and draw me in to the music — sometimes even the venue of the music. Incredulously, I give this evaluation from the recliner beside the official listening chair. With the TubeMagic monoblocks the soundscape did not collapse to the speaker in front of me, though it did lean heavily in that direction. When I sometimes swapped seats with Tom everything fell into perfect perspective. On a good recording the orchestra would be perfectly laid out, left to right and front to back. Furthermore, the tweeter seemed more properly balanced once the bass was extended and the midrange was more accurately centered between the bass and treble. Overall, it was pretty close to Being There. The piano sounded like a real piano. I could hear the hammers hitting the strings.

Parachutes, My Love, Could Carry Us Higher.  (Barbara Guest)
This old poem emerges from my subconscious like the gnarled roots of the old maple tree in my side yard bursting through the grass. Long ago I typed it out on a piece of paper and carried it in my wallet throughout the '70s until finally, it disintegrated. I didn't have much discretionary income in those days and likewise, people who can afford a $3000 pair of speakers are not likely to drive them with $15,000 worth of pre and power amps. The more affordable Triode Labs integrated (or something even less expensive) are a more likely choice. After reading my review of the EL84TT, Carl Ng offered to send me their 2A3 Classic Mk2 stereo power amp ($2888 CDN). It had arrived that same day and while Tom listened to classical music I cut open the box and inserted the tubes. It uses a pair of Sino 2A3C (a new variant of the 2A3) from Guiguang, rumored to be a sister company of the more widely known Shuguang, and it is favored by Carl for its sound, fit, looks and price. It looks like a 2/3 scale version of a 300B — larger than you might expect for its 3.5 Watt output.

The rectifier tube is a NOS Mullard GZ32 favored by many, but easily replaced thanks to Triode Lab's unique "Uni-fy rectifier stage" to tune the amp to your preference. And the 6SN7 tubes are OTK Military Grade which is the cheapest 6SN7 you can buy but accurate, neutral and laid back. The amp is Class A with an auto-bias circuit and unusually, it is AC heated by preference. Triode Lab also makes a hot rodded 2A3-S special edition for $3888 CDN with premium transformers and a chassis that will likely satisfy your desire for audio jewelry. The S version is for the connoisseur who not only likes to roll tubes, but roll amplifiers as well.

We put the CD into forward, listened for a brief moment, looked at each other and simultaneously broke out into laughter. This is a seriously good amplifier in spite of its humble appearance. The top end is rolled off. The presentation is dark, being centered on the lower midrange with a full, sumptuous bass. Attack is good, decay is long, midrange focus is very good and the holographic music grabs your gut and pulls you right into the collective soul of the performers. Forget about a subwoofer. With the highs rolled off and the ripe mid-bass you don't miss the lowest octave because you're so emotionally engrossed in the music. In fact, if I wasn't so indoctrinated in the philosophy of the so-called high-end audio, I could call this an end game and move on to another hobby called high fidelity all the while enjoying the music. Should I put this paragraph to rap music? No wonder Carl tells me a lot of his customers with Zu speakers own this amp. These could be the 3.5 most important watts on the planet. And if not these watts, I'd be tempted to ante up for the 2A3-S. (Can you hear me now, Carl?) Combined with the transparency, dynamics and focus of the Zu Union, you get all the pace, rhythm, timing and timbre that's on the recording. You ask about the Chinese Drum cut? It barely required more than the first watt yet the Triode Lab delivered as much slam and more delicious timbre than I've ever heard from this piece. Tom went home about 11 pm and I fell into bed at 2 am after "just one more song".

Looking Good
I've always maintained that the visual design of gear destined for the home plays a role in the decision making process — for some people more than others and often at a subconscious level. This would be especially true for speakers, more so than electronics. The style of most, if not all of the Zu speakers is dictated to a large degree by their use of high-density comp60-HDF (fiberboard) with real wood veneer applied at the lumber mill where it can be applied with high pressure for a more permanent, secure bond. This requires exacting manufacturing in the Zu shop and also precludes the use of curved surfaces, a case of form following choice of material, I suppose. Models are differentiated by the assortment of drivers and a slight tapering from the floor upward in some cases. The form is mid-20^th century modern although careful selection of wood stain or gloss paint and optional anodizing of the driver's ring can result in a look that could be at home in any d้cor except traditional or country. Since contemporary and transitional styling is dominant and growing stronger in the 21^st century, I'd say they have the right look at the right time for most folks. In selecting a review sample I agonized over what I personally liked best — the "kid in a candy shop" syndrome. Ultimately I requested the honey walnut stain with the standard silver ring driver which is one of their most popular combinations. There are lots of other combinations I could live with ranging from sophisticated to pop art but again, you get to choose.

The other major factor in the design is the ZuGriewe acoustic technology which dictates a tall slender design with a rather square footprint. This allows the speaker to have a minimal visual presence in the room, though this can certainly be offset by your choice of stain or paint if you wish to make them more prominent. In spite of the high placement of the driver, with the overall height being about 37" (with spikes), it doesn't seem to require outriggers for additional stability. (It comes with both rounded feet and carpet piercing spikes that allow for tilting the tower backward a bit. I simulated accidentally bumping into them as might happen at a party and they were reasonably stable but they can be taken down if seriously tackled. The single coincident driver arrangement gives the Union a very clean, understandable look that was very easy to live with and attractive enough not to become boring. The fit and finish are of a high standard and it does indeed look like it will last a hundred years as they claim.

Valve Value
At $3000 the Zu Audio Union speaker cost just a few dollars more than my first serious loudspeaker when I joined this hobby back in the early 1990s. Back then it was a scary purchase, being three times what I had spent on my previous speaker nearly twenty years prior to that. But speaker design has made enormous strides over the past four decades. At $3000 the Zu Union speaker may be close to entry level in price, but it is very close to the best sounding speakers when paired with first class electronics. After our listening session mentioned above, my friend Tom wrote back:

"In terms of value, I was trying to think about other speakers that I've heard that I think can compare with the combination of the Zus and the Tekton subs. The Coincident Total Victory might be a contender. I remember that they sounded quite magical on my Sonny Rollins LP, and I think that was with your CAT preamp, the Mahis, and the unmodified Linn with the Clearaudio cartridge. Other than that, I think that you'd have to go to the level of the Wilson Sashas, the Magico S5s, and the MBL 116s, all about $28k. You can probably come up with your own list. I think that it's an interesting exercise that highlights the value of the Zus."

In terms of transparency and jump factor, the Union might even top these esteemed speakers. In terms of ultimate refinement it comes up a little short, probably because of the minor resonance of the cabinet, but the difference is small enough that poor set-up skills or unfortunate room dimensions could easily reverse the outcome. Whether you get it right or not could be a $25,000 gamble. The issue of suitability for classical music may be linked to the Union coming up a little short in ultimate refinement. As much as Tom liked the Unions with other material, it did not come close to his experience of live music at the RPO, which rules them out of contention for his next purchase. As good as the ZuGriewe tuning is in the Union, the cabinet is still rather light weight in comparison with the Coincident, Wilson and Magico mentioned above, or my reference Kharma speaker. With those speakers the music completely gets out of the box. With the Union, some of it seems to get tripped up. Or maybe the issue is asking the 10" driver to handle the music all the way up to 12 kHz, something that could cause Tom to complain about the violin strings sounding steely. In my house, classical music is rarely heard and opera is banned. Oh, I may have a token Pavarotti LP somewhere, I suppose. For everything else, the Union provided a transparent window that let the music jump right through. If you have the courage to spend a little less for your speaker and a little more for a good tube amp, the Union is an incredibly good value.

I've skipped over technical discussion of the Zu driver and their relationship with Eminence, a major pro audio speaker manufacturer. Nor have I mentioned their proprietary cable design, also used in the internal wiring of the speaker. It is so proprietary I have nothing to say about it save that it's copper and apparently it does a lot of things very right. Combing through their website I came to appreciate that Sean Casey and Zu are a lot more steeped in science than their casual presentations at audio shows suggest.  It also documents the significant technical evolution of this relatively young company which bodes well for their future. Consider their website recommended reading, for sure.

As The Sun Sets Over The Bonneville Salt Flats...
People with lots of money and top shelf electronics will probably snub their noses at this $3000 speaker. Those who are emerging from the weight of college loans will see it as a beacon of hope. The Union is a chameleon that will rock you with down and dirty electronics at the start of your musical mystery tour and lead you step by step as you upgrade your other gear and educate your ear. With the addition of quality subwoofers and finer electronics they become a true full range speaker capable of challenging the most revered names in the industry in many parameters. Even without subs, with their 99dB/W/m efficiency they are a magnet for low powered tube amps that will set you up for a musical experience that will reach you at both a cognitive and emotional level. With their outstanding transparency and uncompressed dynamics the Union took me closer to the live event than any speaker in this price range has a right to do. Every audiophile should have the experience of hearing their music without compression for at least one period in their lifetime. For me, the Union is like a return to the Voice of the Theater but at a much higher level — one that recalibrates my concept of fun and rejuvenates the joy of music. I've left a lot unsaid about them, but the sun is setting and it's time to fire up the amps. There are a thousand LPs I'd love to hear through these speakers.

Specifications
Type: High sensitivity loudspeaker
Driver Complement: ZuCX/ND-8, 10.3” full-range nanotech driver and ASD 1001 tweeter
Frequency Response: 45 Hz to 22 kHz
Component Tolerances: Better than 0.5% driver pair matching, 0.1% on all other components
Sensitivity: 99dB/W/m
Impedance: 8 Ohm, nominal full bandwidth
Connection: Five-way binding posts
Cabinet: North American made high-density comp60-HDF composite, real wood veneer
Warranty: 5 years limited on cabinet and drivers.
Price: $3000

Company Information
Zu Audio
Ogden Commercial Industrial Park
3350 South 1500 West
Ogden, Utah, 84401

Voice: (801) 627-1040
E-mail: info@zuaudio.com 
Website: www.ZuAudio.com