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Reviewer: Michael Lavorgna
Analog: Rega P3, Denon DL-103 cartridge, Auditorium 23 moving coil step up
Digital: Sony Playstation
Tuner: Voice of Music AM/FM Stereo Tuner model 1465 (1960s vintage)
Preamp: Shindo Laboratory Monbrison
Amp: Shindo Laboratory Cortese F2a, Fi 45 Prototype, Fi 421A, JC Morrison 6B4G monoblocks, Red Wine Audio Signature 30
Integrated Amp: SAC Thailand Minute
Speakers: Auditorium 23 SoloVox, DeVore Fidelity Super 8, The Horn Shoppe Horns (original 108Σ version)
Cables: Shindo interconnects, Auditorium 23 Speaker Cable, PHY interconnects
Stand: Finite Elemente Pagode
Accessories: Wiremold L10320 outlet strip, PS Audio Ultimate Outlets and AudioPrism Quiet Lines. Room damping provided by lots of books.
Room size: 13' w x 16' d x 9' h
Review component retail: $9,500/pr
Staid
Enthusiasm is a queer thing, isn't it? I guess I should clarify - queer when exhibited in others. After all, our own enthusiasm is fine but please, the last thing I want to see is someone else gushing. And if this gushing happens in a hifi review, the believability factor necessarily diminishes.


I think it has something to do with the display of emotion. We tend to cringe when grown men let exuberance bubble to the surface. It can be awkward. It can lose elections. Besides, we all know that emotions are the antibody to intellect. If we're really excited about something, we can't be thinking rationally. Can we?


So I'm going to take all my enthusiasm, stick it in a jar and snap a piece of saran wrap over the top. Sealed. Nice and tight. Like a drum. Turn it upside down, shake it and still none will escape. There now. I feel better. Let's get on with it.
Auditorium 23 SoloVox
The man behind the company Auditorium 23 is Keith Aschenbrenner. Once again (and this nearly goes without saying), Jeff Day has done a great job introducing us to Keith and his company in his review of the A23 speaker cables and step- up transformer. I want to stress that you should read this review because it also contains many insights into Keith's approach to speaker design. Here's just one tasty and telling morsel: "Many people didn't understand that ours was simply a different approach to arrive at the same result desired by us all - musical realism. As for us, we only wanted to get closer to the music - no more and no less." I've included Keith's answers to some questions I posed at the end of this review in their entirety. I also count this as essential reading for anyone intrigued by the SoloVox.


There's a host of additional reading on the open baffle theme. Jules Coleman penned an excellent and extremely informative review of the SoloVox which is available through importer Tone Imports website. For more info on the open baffle experience and an excellent lay of the land, check out the reviews by Kari Nevalainen of the Jamo R909s and Steve Marsh's Blue Moon'd Bastanis Prometheus MKII. There are also numerous forums dedicated to the DIY open baffle approach including those on AudioCircle and DIYAudio.
Germane to our focus, Auditorium 23 is based in Frankfurt, Germany and was founded in 1980. Scattered through the company's early history are many horn-loaded designs using classic approaches like Voice of Theater and Onken cabinets. There are also many years of direct first-hand experience with classic loudspeakers and drivers from Siemens Klangfilm, Western Electric (the 755a a particular favorite), Altec Lansing and others. Their influence on the development of the Auditorium 23 loudspeakers should not be overlooked or underappreciated. Their first single-driver speaker La Petite L´Audiophile utilizing a Fostex 103 Sigma driver was introduced over 20 years ago.


Auditorium 23's first open baffle speaker the Provence incorporating the 8" PHY-HP H21 LB15 driver was released in 1997. Keith sees this particular PHY driver as the most successful modern implementation of "what Radio France was using in the fifties and sixties as a wide-range unit for broadcast purpose". There were three more designs prior to the SoloVox, each a refinement of the basic principles of the Provence. We can also see a progression of the concept of the speaker cabinet as soundboard taken to its literal extreme in the Appassionata, through the use of the same wood that's used to make piano soundboards - the resonant nature of a musical instrument applied in controlled measure through craft and implementation to the speaker's wooden body. If I can simplify this particular approach to a catch phrase, it would be the pursuit of tone.


Perhaps the most famous -- or shall we say infamous -- in this series of open baffle designs is the Rondo. "Again, the design follows the rationale that a loudspeaker housing is comparable to the corpus of an instrument; it should use rather than eliminate energies from the driver. Thus we carry on a tradition of reverberating housing concepts that Western Electric and Altec Lansing first formulated in the Fifties."

The thin-walled Rondo, which made its debut at the Frankfurt High-End Show in 2000, was by all accounts a success. As Keith readily admits, it was rooted in historic designs. Yet it stood apart and on its own. If imitation is the sincerest form of flattery, the Rondo was sincerely flattered by many admirers.


As the Rondo embodied many of the principles contained in A23's previous speakers, it's easy to see their in-house heritage, the subtle refinement of shape and materials over time to form the curvaceous Rondo. When you come across other similarly-shaped open-backed cabinets housing a PHY driver, I'd suggest looking for a similar in-house heritage. From my way of viewing, I can trace their lineage directly back to Keith Aschenbrenner and Auditorium 23.
The SoloVox came directly after the Rondo. In some ways it is the culmination of the knowledge gained by working with the same 8" PHY driver in an open baffle cabinet these past ten years, combined with a reverence for the classic designs from our shared
hifi heritage. The SoloVox is the first speaker in a new line of A23 products - Hommage. "SoloVox, as does the entire Hommage line, represents a modern implementation of the principles and standards that defined the greatness of audio reproduction in the first half of the previous century. SoloVox loudspeakers are produced in limited numbers reflecting a commitment to produce the very best possible component and to highlight their uniqueness. These are not loudspeakers intended for everyone, and they do not represent a mass market effort to make yet another loudspeaker. The SoloVox is anything but just another loudspeaker."

Beyond the unique cabinet of the SoloVox, there is a new and proprietary driver from PHY-HP. To my eyes, the PHY driver is a thing of beauty. Utilizing a paper cone, massive bronze basket, mounting ring and Alnico magnet, PHY crafts these drivers in old-world style. They are also extremely limited excursion drivers and as such will take a very long time to break in. Think a few hundred hours. You can check out the specs on the stock driver on the PHY website. There's an interesting comment from PHY regarding these measurements worth sharing:
"These characteristics have an indicative value and are only the result we generated in our anechoic chamber from measuring equipment actually in our possession. It always must be kept in mind that the main values such as the natural equilibrium and musicality, cannot be described by this method and are only partially derived from it."


Since this driver is proprietary to A23, any admirers and handy men can only approximate the SoloVox. It appears as though Keith might keep the SoloVox's musical affairs private this time. C'est la vie.
The SoloVox stands approximately 41 inches tall, a stout 20 ½" across its front and 12" deep. The cabinet proper is actually a smaller dimension since it's stand-mounted. The in-built metal column legs keep the driver about 32" off the floor. Under the wooden plinth are four thin steel-threaded points. They are individually adjustable and A23 recommends a slight rear-leaning rake. Cabinet construction is various thicknesses of beech plywood and the SoloVox weigh a svelte 44lbs a piece. The basic shape of the baffle is rectangular with all curved corners. A portion of the sides and the entire back are open. Around back are two curved

wings inset a bit into the support structure. These wings assist in deflecting the rear waves of the driver sideways which otherwise would interact directly with the wall behind. Construction quality is flawless.


There are no standard binding posts and the SoloVox will only accept banana connectors. Since I use A23's speaker cables, this presented no problems. I'd go so far as to suggest that any SoloVox owners should avail themselves of this in-built synergy. I'll admit upfront that I did not try any alternative speaker cables. My reasoning was simply that I could not see any point in this exercise. Rated at approximately 96dB and 15 ohms, they are an easy load to drive.
Venturing into the land of aesthetics, I find the SoloVox a visual delight. One look around my listening room would suggest a similar sensibility. As is the case with any speaker and even more so with an open baffle, room and room placement are critical. Since
the SoloVox fire in a number of directions, it follows that they will interact with your room unlike a typical speaker. This interaction can either wreak havoc or bliss depending solely upon placement. In addition, the resonant character of the wooden body is very sensitive to room-induced peaks. I can say room-induced with total confidence since through careful placement, there are no resonances or peaks to be heard. I've also listened to the SoloVox in a few other homes and it was the same in every case - no peaks, resonance or shout. Patience and time are a prerequisite to getting the most from the SoloVox.

In fact, it took me a few weeks to get the SoloVox properly placed in my 13' x 14' (16' including the bay window) room. Since I work from my listening room, I can afford to spend a considerable amount of time tweaking. As a matter of fact, I rearranged my entire room a number of times which includes moving over 600 books. From wall to wall. And back again. Long wall, short wall, 22 degree, 45 degrees, nearfield, near-wall. The spot that turned out to be the spot was a few inches from where I'd very nearly began. Without exaggeration, the SoloVox are sitting within inches of where I had them situated - but they sound very nearly like a different speaker now that the wall of books is behind them and the distance from the wall increased a bit.


My advice for any new SoloVox owners - this is ideally a two-person job. The SoloVox will tell you very clearly when they are happy and this process can be simple and painless with one person doing the moving and the other the listening. My family preferred to keep a safe distance and watch the proceedings with no small amount of amusement. "Are you really going to move those books - again?"


I also tried every amp I own and they were all musical partners. In the end, the newest entry in my stable, the Shindo Cortese F2a, was the favored mate. The Cortese has an uncanny ability to energize music so it sparkles with purity and life. And for those who've read Jeff Day's Auditorium 23 review, this synergy will come as no surprise. Keith is the Shindo Distributor in Germany and he stopped building his own electronics once he heard Shindo. "When we got the first Shindo amplifiers and connected them fresh out of the box, all of our taken-for-granted musical hierarchies were demolished. This was the next big breakthrough on our path towards musical realism. For us it was the end of DIY amplifiers - we simply surrendered to the obvious superiority of the Shindo Laboratory products". The SoloVox were voiced (or nurtured) on Shindo and vinyl.


Theoretical Bests and Musical Firsts
So what does the SoloVox sound like? In my admittedly brief time as a writer about listening, I have never felt the pinch of futility as sharply as when I sat to pen listening impressions of the SoloVox. There are a few reasons for this. First off, to analyze the sound of the SoloVox in typical hifi speak means one has to ignore the music they make. This has proven to feel very much beside the point. Secondly, I already own the SoloVox and have spent over a year listening to and thinking about them so writing about them now is a tad regressive. They also fit my personal preferences to the veritable T. And finally, I know the US importer for Auditorium 23, Jonathan Halpern of Tone Imports and consider him a friend. But as hard as I tried, my enthusiasm for the SoloVox stretched that plastic wrap of detached intellect to its limits. Snap!

Perhaps most striking upon initial listening is the way the SoloVox energize your room while they seemingly evaporate. When properly set up, there is no sense that any of the music you're hearing is coming from the speakers standing in front of you. None. In addition, the music's energy is not only detached from the speaker, it is in no way confined to the size or shape of your room. So it pulls a double disappearing act, first the speaker, then the room. The next thing I noticed about the SoloVox's music making was the shape of the sound - which is full. I'm not talking about soundstage width and depth (although that aspect is there as well for anyone so inclined) - I am talking about the perceived shape of the music. There's fullness to the musical presence, a dimensionality that sounds as natural to my ears as any speaker-induced response I've had.


On the potential downside, their presentation is admittedly much less physically forceful than any box or horn-loaded design I've heard. And perhaps as Jules Coleman pointed out in his review, they sound less forced because of it. The closest I've heard to this aspect of their presentation are the original Quad 57s. Dipole designs tend to throw the perceived sound source away from the speaker. As such, the physicality of something like a multi-way cabinet design with a stack of 15" woofers ("man that thing can move a lot of air") is absent in the SoloVox. You don't feel the music, you hear it. It's much more of a sensual as opposed to physical experience. One could reasonably conclude that metal headbangers and three-cornered-hat listeners may want to look elsewhere for their brand of sonic satisfaction.
So far, I believe we'd be inclined to attribute these traits to any more or less successful open baffle design. And I won't argue that point. If you scour the posts on some of the open baffle forums and read the above mentioned
reviews, I think you'll find these observations are common to the implementation. Where the SoloVox excel is in combining these traits with timbre, timing, dynamics, articulation, resolution, macro detail, micro detail, coherence, control, attack, decay, delicacy, focus, inner detail, pace, snap, speed, texture... and any and every other adjective we can come up with to reinforce the idea that you're listening to music more than you're listening to a pair of speakers. Here I'd rank the SoloVox among the best I've heard. The result is that I'm hearing into the performance in ways I never experienced before. The startling thing isn't that a sax sounds so much like a sax (which it does), it's the way it's being played that gives one pause.


But are they really full range? Will my dishes rattle and my dogs bark? The published specs for the stock PHY H21 LB15 have them going down to 45Hz in the PHY anechoic chamber. I'm getting audible bass below 40Hz (down about 5dB using my trusty test-tone CD and in-built bio-frequency analyzers). And up top, we roll off after 12kHz or so. No ultrasonics, no rumble. But you already knew that, right? After all, I know of no true single driver speaker that will do the 20-20 full-range jig. Come to think of it, I don't know of many speakers of any stripe that will.
Starting place of layout

Why is it then that most single-driver speaker reviews seem to be apologetic about bass response? As if a true single-driver design is going to leave you bass-hungry. A lot of multi-driven floorstanders don't crack the 40Hz mark and many monitors mainly hover above 55Hz. Hell, if a monitor breaks 50Hz, it's a cause celèbre! And a single-driver speaker that delivers the same 50Hz is somehow restricted? Maybe it's just that problematic 'full-range' moniker which I never liked anyway. And maybe some guys still just get excited when something little can perform kinda like something big. Beats me.
Final place of layout - within inches but completely different ballgame

The single-driver or wideband descriptors seem much more accurate and avoid the issue completely. So I'll make no excuses and go so far as to say that the wideband-endowed SoloVox bass extension is entirely adequate in my book. After all, adequate is about as excited as I get when talking about reproducing test tones. More importantly, I find the lower frequencies produced by that single 8" driver in that open-backed cabinet to be fast, tuneful and musically convincing. It's also a cohesive part of the musical whole which is one of the thornier issues I've heard with single-driver speakers that attempt to plumb the depths by augmenting them with a powered sub.


If it's sonics you're after -- meaning if there are various aspects of sound that appear high on your listening priority list like things you can measure -- I would not bother with the SoloVox (or any true single-driver speaker for that matter). They are not impressive speakers in those terms. If you have a large room and like to fill it with very boisterous music at ear-splitting levels, the SoloVox may not be for you either. They are not dance speakers, party speakers, home theater 2.0 speakers (soundtracks with impressive effects may not be as impressive as you'd like); they are not even hifi 2.0 speakers. They are listener's speakers in every sense of that word. As such they are among the most musically engaging speakers I've ever heard.

And no matter the musical genre, the SoloVox lay it out there for you to explore. I do not find myself limited to what I want to hear - anything is fair game (bear in mind you will rarely if ever have to shout in my ear to get my attention when I'm listening to music). There is such a startling difference to be heard within music played through the SoloVox, the only downside I've come across to date is the cost of all the LPs I've been buying. For the last few months I've owned and lived with the SoloVox, my musical addiction has grown. It's not that I listen longer - I listen deeper. I've taken a keener delight in interplay, phrasing and the silence between the notes.
Uncorked
When we listen to our hifi, all our rapturous energy, all that excitement and nearly uncontrollable enthusiasm when things work, necessarily leaves the hifi behind. What? You mean the thing we've pained over, strained over and paid sometimes dearly for becomes beside the point?


I say absolutely. Getting enthusiastic over hifi is dorky. It is clubby in the sense that it looks like very strange behavior to the uninitiated. That's because we don't always focus on the point of a good hifi which remains nothing more and nothing less than playing our music. If we shift our enthusiastic eruptions to the experience that music holds, we're back down to earth proper. We've left the listening room and rejoined the party. Music is worth the time, trouble and expense. Hifi for hifi's sake isn't.


Are the SoloVox for everyone? Isn't that such an obviously absurd question? For me it stands directly next to "Are they the best speakers in the world" in the master list of silly questions that signal a basic misunderstanding of the basic point. And that point is, we all don't listen to or for the same thing. The means are necessarily different because the ends aren't the same. Asking me about frequency extension for example makes about as much sense to me as walking through the Museum of Modern Art looking for the painting that looks least like a painting. And I have willfully and consciously avoided the whole topic of cost and perceived value which to my mind are utterly subjective.
Ultimately and obviously. the choice is simply a personal one. For me, the SoloVox sat at the crossroads of every audio thread I was following. And these threads go back years. You can trace my interest in PHY-HP back to my first review for 6moons in March '05. I'd owned single-driver speakers and single-ended amps for years prior to joining 6moons and have made it a point to hear as many as I can. I'd been eyeing and earing Shindo electronics for just as long and recently purchased the Shindo Monbrison and Cortese F2a. I also own the Auditorium 23 speaker cable and step-up transformer for the Denon 103. So in some ways, it was nearly inevitable that I listen to the SoloVox. And the most telling conclusion to this aspect of the story is, I bought 'em.


What the SoloVox do, they do as well as any speaker I've ever heard. And the main thing they do is present music in a completely natural way, devoid of any perceived barrier between you and it. And this is not an illusory experience. It's a sensual experience. This distinction bears clarification. I'm not suggesting that when listening to music, I actually think there are musicians playing in my room. I'm not tricked or fooled. What I'm saying is that the act of listening can overcome conscious thought. It's a sensually saturated experience. And this momentary mental derailment is not only welcome, it is something I crave.
Don't get me wrong, I'm not suggesting this is a mindless activity. Far from it. I'm just stating the obvious - experiencing music (or any other form of Art for that matter) is not a solely intellectual activity. It's also not entirely emotional. It's a blended delight. A heady, heartfelt mix set off and led astray by our music. The SoloVox are unlike most every other speaker I've heard and their difference reveals itself as a stripping away of the artifacts of reproduction, leaving you and your music alone together.
Manufacturer's website
US importer's website
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