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This review first appeared in the January 2007 issue of fairaudio.de and can be read in its original German version here. It is herewith translated and presented to an English-only audience through a mutual syndication arrangement with fairaudio.de whereby they will translate and publish select reviews of ours while we reciprocate with one or two of theirs each month. As is customary for our own reviews, the writer's signature at review's end has a link below it to his e-mail should you have questions or feedback you wish to send. All images contained in this review are the property of fairaudio.de - Ed.

Reviewer: Ralph Werner
Sources: Analog - Acoustic Solid MPX; Phonotools Vivid-Two; Denon DL-103; Ortofon MC Rondo Bronce; digital - audiolab 8000CD; Esoteric SA-10; C.E.C. TL51XR
Amplification: integrated - LUA 4040C; Mastersound 300B SE; preamp - Bel Canto Design PRe 3; Funk LAP-2; power amp - Bel Canto Design e.One M300 monos
Loudspeaker: Spendor S3/5; Volent Paragon VL-2; Zu Audio Druid mk4
Cables: low-level - Ecosse Baton + Symphony, fis Audio Studioline, fis Audio Livetime, Funk BS-2, van den Hul Integration Hybrid, Zaolla Reinsilber NF; high-level - Ecosse SMS2.3, fis Audio Livetime, Ixos 6006 Gamma, Zu Audio Libtec
Power distribution: Fis Audio Livetime
Rack: Creactiv & Taoc AS-3, Gerätebasis der Akustik Manufaktur
Review component retail: starting at € 5,300r/pr
Flat x diffuse = deep?
I'm not committed to exotica but off-the-cuff products, I admit it, do exert their magnetic pull. Hence there was no way I could have possibly stayed clear of Podium Sound Ltd.'s loudspeakers. Everything is different here, including the inventive brain that birthed them. My first exposure was harmless enough and entirely coincidental. I nearly overlooked Podium's display at the Munich HighEnd 2007 show. In fact, had it not been for Herr Linzey's insistence in the hallway to enter their -- let's be frank -- utterly stark and naked chamber, I'd not have entered. A new panel speaker? Why not I shrugged...


The Podium Model 1 playing inside proved of the fast sort. Percussion, piano attacks, impulse responses of any sort presented zero challenges. No great surprise there with that big panel I figured. Yet I was surprised by the good tonal balance and even more by the terrific ambient dimensionality recreated in this piss-poor dungeon
of a room. Queried whether I was dealing with an electrostat or planar magnetic, I was promptly greeted by a noncommital grin and a "neither nor" retort. My first eye brow lifted. To extract a full Jack Nicholson, Mr. Linzey next turned one of the speakers sideways and thus parallel with the side wall. The bloody soundstage remained more or less intact. My second eye brow raised and a promise followed to revisit with my colleague in tow an hour later. Good timing it'd be too I was told. Designer Shelley Katz would be present then.
Had I expected an engineer who began his hifi meddlings on dad's pride'n'joy speakers at the ripe age of 12, I'd been sorely disappointed. This designer was a musician first - a pianist to be exact. And a conductor and composer. Canadian-born, Herr Dr. Katz began his musical studies at Quebec's Conservatoire de Musique and continued at the renowned Julliard school in New York, concluding with a bachelor and Masters on the piano.


This was followed by a solid career which "got him decently around" - as pianist for the New York Contemporary Ensemble, during performances in the Vienna Musikverein, in London's Wigmore Hall or Tokyo's Suntory. His collaborators' names read equally impressive: Skrowaczewski, Bernstein, Solti, Nicolai Gedda, Gwyneth Jones, Jochen Kowalski ... yet now he builds speakers. Go figure.


Off the beaten track ...
...seems leit motif and MO with this British import (Herr Katz resides in Cambridge where Podium Sound is based). After all, successful classical musicians
don't normally cross over to loudspeaker design. But forget normal thrice over with the actual speakers, including today's review subject the Model 0.5, the second smallest of the bunch.
At 140cm tall, small is admittedly relative. But the Model 1 stretches to two meters and an even taller Model dubbed Ultra currently under development will proudly exceed even it. Then there's a smaller 'un called Model .25. Needless to say, distinctions between models exceed mere size but common to all is a crossoverless widebander concept driven from traditional electrodynamic voice coils to induce bending-wave resonances in the panels. This very efficiently -- one might add systematically -- negates all pistonic ideals of point source behavior in one fell swoop. Wild, eh? How does one even arrive at such a bizarre concept?


By working with and experimenting on electrical pianos. That's precisely what Mr. Katz was up to during the 80s while playing in German opera houses. Aside from certain advantages of digital pianos, he wasn't much impressed by their sound. Even with the best of the breed, he found their sound "electronic and unnatural". The question of why so haunted him that after immigrating to England, a dissertation on "Cognition of Expression in Music" for the Surrey University became the framework from which to pursue this subject further.


A practical outcome by 1998 was an e-piano which finally conformed to his expectations of natural sound. Insights won during the process then pooled into subsequent loudspeaker design where the core notion was a vibrating panel, a seemingly natural extension for a pianist who is used to a soundboard which amplifies string resonances that are coupled to it via a sound bridge. Needless to say, such a soundboard is supposed to not merely activate at self resonance but to amplify the entire bandwidth of the piano in discrete steps.
The principle of how a resonant panel couples to the surrounding air to propagate sound differs from conventional dynamic loudspeakers. The latter rely on ideally pure pistonic behavior wherein bending waves, standing waves and resonances of, on and across the actual diaphragm are undesirable and to be avoided at great costs. Contrast this to a sound board or panel speaker where vibrational input from the bridge or voice coil causes transverse bending waves of different amplitude and phase in different locations. The resultant sound transmission is necessarily diffuse in nature and the goal becomes a homogenous wideband radiation of sound waves that are differentiated in the time domain and spatially in the direction of travel across the panel's surface.
This is one of Podium Sound's core contentions: Conventional dynamic drivers are well suited to reproduce direct sound but completely fail at diffusive sound quite on principle. Attempts to overcome that shortcoming with surround sound or DSP manipulation are silly patch work. An ideally perfectly pistonic point source can never be a diffuse sound generator. But the latter is essential and precisely what Podium Sound speakers have to offer.


It's an interesting theory in need of further elaboration. To match the sound and sound propagation of acoustical instruments with a loudspeaker was merely one of the goals to develop a diffuse-sound loudspeaker (but to Shelly Katz, it is fundamental as to why 'normal' loudspeakers sound like speakers and not real instruments). Another goal was the desire to approach "the sound of acoustic instruments in a concert hall", with strong emphasis on "concert hall" or more generally, the recording venue with its specific room acoustics. Correct reproduction of the latter is said to be significantly superior with a diffusive speaker and a more powerful ambient overlay on the playback acoustic becomes the promised outcome.
Two points could be immediately disputed. One, instruments or general acoustic events can and do embody direct-sound qualities. Two, the relationship and time delay between direct and reflected sound in the replay venue affect this matter. If a loudspeaker concentrates solely on diffuse radiation, doesn't it lack a vital parameter? It does. The associated "but" includes two justifications: One, the Podium speakers are ultimately compromised because resonating transverse wave panels are intrinsically handicapped when it comes to pure direct sound. (The same must be said for traditional dynamic transducers, just in reverse).
Two, the Podium Sound enterprise is a spin-off of a larger research project under the umbrella of the research and patents belonging to the company and trademark of Layered Sound Technologies Ltd. Here Herr Katz is its director and the basic idea there is to combine the respective strengths of direct radiators and panel resonators. Obviously, the project brief of creating a suitably home-approved Layered Sound loudspeaker system is quite
daunting. With theories necessarily about ideals but years' worth of R&D in need of commercial support, this ambitious project kicked off with the construction of a 'basic' panel speaker and to this end, Podium Sound was launched in December 2006. Actual Layered Sound applications do already exist, albeit not yet in consumer Hifi but commercial environs of theaters and performance houses (with the Musical Dome in Cologne and Capitol Theater in Düsseldorf two examples). The panel speakers in those installations are by NXT whose basic resonating panel principle is the same as Podium's but differs in actual implementation. Heck, even the term 'dynamic transducer' covers its own number of varietals...

Theory should always be followed by experience so a closer look at the Podium Point Five is due just about now. Overall dimensions are 140 x 61cm and the frame is 2cm thick. The back reveals a kind of spine right down the middle which, when viewed from the size, reveals a minor wedge profile that enlarges downwards. At the bottom of this spine sits a hole to receive a 35cm steel floor brace. The Model 0.5 stands on three feet: Spikes left and right plus that rear brace.


In standard trim, the frame is crafted from massive English Oak while a 400 Euro surcharge can upgrade to Cherry, Maple or Walnut. Piano gloss black (how fitting) and white will shortly be added on demand. The permanent cover is black or crème white. Because every Podium speaker truly is crafted by hand, there's a two-week turnaround from order placement, quite prompt for any custom furnishings. Heck, unless I sourced it from Ikea, all of my household fittings took longer. Even though some don't fancy solid woods, execution here is simply perfection incarnate to strongly differentiate this product from the - ahem, general Ikea crowd.
Four strange holes along the spine expose metallic innards. These are the actual motors, i.e. traditional voice-coil/magnet units. A single-wire input terminal expedites the electrical signal via silver conductor to these exciters. There's no crossover but a single resistor does match impedance for easier load behavior.


The driver magnets are firmly mounted to the wood and each voice coil couples directly to the resonating panel to cause movement. It's readily apparent that the physical makeup and shape of the panel will greatly influence how it'll sound and whether it will conform to Mr. Katz' ideals of natural sound.
The actual diaphragm is a honeycomb Nomex paper sealed between transparent polyester foil. This material combination was chosen for its light weight, long-term stability and ease of fabrication. Its most important attribute however is its capacity "to ring like a bell". It's a statement which standard speaker makers
would stay clear of like the pox but then we're dealing with a very different operational principle here. On the panel, the exciter motors induce a chaotic mix of bending waves in different locations. To create a homogeneously balanced acoustic output from that becomes the relevant art. Accordingly, each and every Podium loudspeaker is truly tuned by ear and hand to have Mr. Katz view his work foremost as that of an instrument builder. Computer modeling is completely unfit to perform this vital tuning.

The rounded corners are no coincidence. They are said to "steer" the bending waves in the desired direction. The choice of glue between motors and panel is vital as is the edge treatment where the greatest turbulences occur. The sealing of open honeycomb cells where the material was cut becomes important - and doing so without imposing an unwanted damping effect. Further tech talk mentioned sound bridges which strategically connect the panel to the wooden frame in certain places to mix transverse waves. Even the exact spacing of the exciter motors is important and different from the Model 1 where, sans crossover, different motors are somehow dedicated to specific frequencies even though the entire panel radiates all frequencies. Truth be told, I remain confounded by how such a speaker can even begin to work. I take it at face value then how devilish the handcrafting tweakery has to be to even pull it off, never mind make it sing.


Not only are the developer and his creation "different", so is the sound. Those who are spoon-fed on conventional dynamic transducers and thus already immune to the charms of regular panel speakers will likely find the Podium speakers "completely wrong". The sonic picture occurs far in the distance without dynamic low-frequency kicks and while the high end is clear and precise, the Podium 0.5 is far from being an atomic microscope. This could be an area even panel aficionados will fault since the casual eye will see a panel and assume that it should resolve the smallest of dust motes or otherwise be disappointing.

Admittedly, I couldn't peg this speaker right away. It took time to sort out its strengths and weaknesses. At first, I was simply confused. Let's step closer then.


Tonally speaking, the Podium .5 sits in the middle, albeit in the lighter upper third. Low-bass freak shows are expectedly cancelled but at one or two octaves higher, the bass becomes surprisingly good - quality over quantity; fast, dry and slim in mass. I barely missed a thing on acoustic instruments but did some on rock albums. How does Shelley Katz so aptly put it on his webpage? "We make no apologies for the simple fact that currently, they will not make lovers of Reggae and heavy rock music completely happy", and then, "those individuals will simply have to wait for one of the products we've still got on the work-bench. However, rest assured, they're coming!" May I pencil myself in on that waiting list, Mr. Katz?!


It won't require emphasis to proclaim that the Podium .5 is no disco speaker. That doesn't mean it won't go loud. It will. That said, I don't consume classical, Jazz or partially electrified music at excessive levels. On the occasion that the Beatsteaks are expected to wreak havoc in my living room, I'd skip the Podium 0.5 as plainly the wrong choice even at modest SPLs.
In matters of speed, impulse response and rhythmic fidelity, the Podiums run at the head of the class. Those bending waves seem to travel across the panels like greased lightning. This is particularly noteworthy on percussion -- a snare simply comes alive -- but anything with speed like piano attacks, guitar plucks, rattles... even Harald Johnsens' double-bass fingering had rarely been conveyed this immediate and sudden [Tord Gustavsen Trio Changing Places]. Good stuff.
Moving right along, secondary noises endemic to music making -- chair creaks, foot taps, a choked cough in the fifth row -- no longer are mere background filler. To an uncanny extent, the Podium 0.5 turns these involuntary noises into integral performance parts. Seeing how I'm among those who would deliberately mix a few coughs into a pure studio production just to spike up the live effect, I'm particularly taken with this quality.
In matters of localization sharpness and outline precision, you'd assume utter fogginess. After all, how is a diffuse source supposed to stage with precision? As it turns out, surprisingly well even though it clearly does not use the sharpest pencil nor draws out a road map with tightly clustered little flags. Rather, it's an allocation of placement within a grand musical picture -- here, there and yonder -- not a strict grid. Make no mistake, plenty of classic dynamic speakers outline no sharper and those sick of the small-checkered Hifi Sound in particular will freely gravitate to the Podium sound.
Which gets us to the most confusing bit: the spatial depiction. The soundstage is huge and decorrelated; so far, so good. But the music plays well behind the speakers and the stage is simultaneously far deeper than usual. It feels as though one were looking into one giant container whose walls were barely visible and whose entrance didn't coincide with the speakers' starting line but a few steps behind it. Then you simply kept going deeper and deeper. And now envision this with your ears, not eyes... as I said, confounding.


Perhaps habit has caused certain acoustic expectations in me. When a speaker stages more laid-back, it appears to be flatter since front-to-back distance foreshortens which I equate with a less intense, less involving experience. This personal perspective is likely why I've always well tolerated forward-staging speakers. If 'front' means within arm's length, 'back' means four steps over there, hence deep (if the speaker can resolve layers in the first place that is). To remain with this concept, with the Podiums, you gotta walk three steps to even meet 'em and then there's six more steps to go to get to the end of 'em...
That I had a hard time relating to this effect probably had to do with my unintentional but initial restriction of musical choices to studio productions. Calexico spins and I think how interesting it is that the drummer plays two rooms over. But what was the
Podium trying to tell me? Was this right or wrong? 'twas fascinating no doubt but...


Then I cued up Arvo Pärt's Tabula Rasa, the needle descended and two minutes later this blind man had a vision. That was the bloody perspective, even the Katz said so! (Of course a certain immunity to marketing claims has long since created reluctance to believe anything.) Simply put, the Podium transports one into the concert hall with a good view on the stage. Or should I call it orchestral podium? Dammit, I just got that. Sometimes I'm a rare slow burner... So, you're not sitting front row but somewhere at hall central. The orchestra is reasonably far away but still clear and easily perceived. Naturally, I can't make out individual violins but the scale of the orchestra and the general grouping is plain as day. What's more, the size and character of the venue are eerily tangible. The artists no longer perform as though in an outer space vacuum but in real, concrete and defined space.
I madly reach for as many classical and live recordings as I can scare up and determine that it is exactly this ability to recreate the recording venue's acoustics in such relief that it renders studio productions weird if perhaps kinkily interesting while live productions become absolutely phe-no-me-nal. Should you place a great value on the illusion to experience a classical concert in the actual concert hall, then I expect there exists no other speaker at this price which pulls off that stunt
with anywhere near this kind of verisimilitude. With such exceptional ambient dimensionality, who cares if a bit more creaminess exists elsewhere? This isn't an advance of a hifi-typical quality to the next level. This is profoundly different and substantially new territory.
That this would be applicable "beyond string quartets" I realized with considerable shock on Tori Amos' live album To Venus And Back, disc 2. I fancy this record for its songs, not the technical fact that it was cut live. In fact, the latter has more than once interfered - audience applause, venue reverb, the diffuse sound; these items tended to undermine my listening pleasure. Yet with the Podium .5, all this became a huge asset. I'd never before experienced this album's spatial dimensions. Now a huge hall beamed down into my living room. And never before did I welcome the applause as a vital live element with such joy and anticipation. Usually it took me away -- as being too distanced or too up close, too sharp, too indistinct -- whereas here it became an elemental part of the performance, well beyond the profane recognition of "ah, applause - must be a live cut"...
Conclusion
'Love it or hate it" might be a bit strong but in the end, it does capture the reactions I foresee to this very unique and different speaker whose performance very much depends on what you play over it. This clearly is no universal speaker (which, ultimately, doesn't exist in my book but you might differentiate my meaning here) and to my ears, its sonic ideals are:
  • More appropriate for acoustic rather than electronic music
  • Especially strong on live performances,
  • albeit not from a front-row but far-field "deep space" perspective

Which doesn't imply that these three conditions are required to meet for things to work. But the closer you meet these ideals, the stronger you shall play to the Podium .5's strengths. Conversely, drum'n'bass won't be on the menu. When everything adds up, the Podium Sound 0.5 recommends itself with:

  • A fascinating recreation of space in width, height and tremendous depth which utterly overlays the playback venue and hence sounds distinctly atypical for HiFi. This is a diffuse-sound speaker with the goal of recreating the recording venue of a live performance. When the recording is up to it, this is pulled off to a degree I've never heard before, period.
  • A good tonal balance with a tendency toward the light side of the Tao. With no deep bass to speak of, the bass that's there is surprisingly potent, fast and dry for a panel this size. Ultrasonics are out of reach but the midband is utterly transparent and clear. Voices are rendered wonderfully as are strings. Piano simply defies words...
  • Precise timing and good toe-tap factor. Percussion is strong, impulses simply arise.

Further advantages include:

  • Easy drive: With a claimed 91dB sensitivity, impedance hovers between 4 and 8 ohm. I drove this speaker with a 300B SET to full satisfaction.
  • Easy to place: Experimentation is always relevant but the Podium is decidedly not a diva. The diffuse character and virtually omni-polar radiation render setup anything but millimeter obsessed.
  • A very wide sweet spot. I won't go as far as claiming that the Podium 0.5 fills the entire room evenly no matter what but you may move on your sofa easily two meters in any direction without penalty.

Herr Shelly Katz, both from a technical and sonic perspective, has clearly pulled a very different and unique speaker out of his hat. Whether this equates to "uniquely good" is personal reaction. As it is, reactions do span the gamut from enthusiastic applause to radical dismissal in the usual HiFi fora. With German distribution in the works (they're primed for calls and e-mails), I hope that opportunities for personal auditions will be ample to afford the Podium Sound loudspeakers the serious opportunities they deserve. Best of luck!
redaktion @ fairaudio.de
Podium Sound website