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Reviewer: Srajan Ebaen
Source: Zanden Audio Model 2000P/5000S; Raysonic CD168; Ancient Audio Lektor Prime; Abbingdon Music Research AM-77 [on loan]
Preamp/Integrated: ModWright SWL 9.0SE; ModWright LS-36.5; Music First Audio Passive Magnetic; Bel Canto Design PRe3; Wyetech Labs Jade; Supratek Cabernet Dual; Melody HiFi I2A3; Eastern Electric M520; Yamamoto HA-02; Trafomatic Audio Experience One [on review]; AMR AM-77 [on review], Red Wine Audio Signature 30.2 [on review]
Amp: 2 x Audiosector Patek SE; 2 x FirstWatt F4; Yamamoto A-08S; Bel Canto e.One S300; Fi 2A3 monos; Coda CX and CSX [on review]
Headphones: AKG K-1000 w. hardwired Stefan AudioArt harness; audio-technica W-1000
Speakers: Zu Cable Definition Pro in custom lacquer; Mark & Daniel Ruby and Maximus-Monitor with Omni-Harmonizer; WLM Grand Viola MkII Monitor with Duo 12 passive subwoofer, Duo amp and Sys V active crossover; DeVore Fidelity Nines; Rethm Saadhana
Cables: Crystal Cable Ultra loom, Crystal Cable Reference power cords; Zanden Audio proprietary I²S cable; Zu Cable Varial, Gede, Libtech and Ibis; Stealth Audio Cable Indra, MetaCarbon & NanoFiber [on loan]; SilverFi interconnects; double cryo'd Acrolink with Furutech UK plug between wall and transformer
Stands: 2 x Grand Prix Audio Monaco Modular 4-tier
Powerline conditioning: 2 x Walker Audio Velocitor S fed from custom AudioSector 1.5KV Plitron step-down transformer with balanced power output option
Sundry accessories: GPA Formula Carbon/Kevlar shelf for transport; GPA Apex footers underneath stand, DAC and amp; Walker Audio Extreme SST on all connections; Walker Audio Vivid CD cleaner; Walker Audio Reference HDLs; Furutech RD-2 CD demagnetizer; Nanotech Nespa Pro; Acoustic System Acoustic Resonators
Room size: 16' w x 21' d x 9' h in short-wall setup, with openly adjoining 15' x 35' living room
Review Component Retail: €3,700/pr
For our third installment of fine hifi from Poland -- Ancient Audio and RCM were the previous two -- let's make a surprise detour. This will serve two points. For his new $24,900/pr flagship speaker, Daniel Khesin, formerly of DK Designs but here for Polymer Audio's website, states the following: "The Polymer Logic loudspeaker features a midrange cone manufactured from a pure diamond, a theoretically perfect material for a sound transducer. The Polymer Logic loudspeaker operates this pure diamond cone over a wider frequency band than any other loudspeaker in existence, in the critical midrange area where human hearing is most sensitive." What bandwidth does this ultra-expensive driver -- grown over one long week in a plasma reactor -- actually cover? That relevant bit goes unmentioned. One does find the 500Hz figure on a subsequent page. It's the hand-over frequency to the "hand-made vapor-deposited titanium woofer [is] currently only available in the highly sought after $20,000/pr Magico Mini monitor". Actually, it also features in the $5,050/pr Volent Paragon VL-2 we reviewed while Magico discontinued its use in favor of a nano Carbon unit. Where exactly does Polymer Audio's gold-covered Titanium Supravox TG1 tweeter kick in? That isn't stated. The prior claim for widest midrange coverage thus remains nonspecific.


With Eryk Smólski's Ketsu S slim tower from Warsaw, there are no such claims. There are simply hard specs. His paralleled 70mm/2.75" paper widebanders, like Gallo's micro spheres, cover 200Hz to 21kHz. They run wide open into the treble. At 14kHz and -6dB, the 27mm/1" bullet tweeter with polyamid dome and 25kHz extension can be optionally inserted into the signal path to improve air and sparkle with tube amps for example (it connects via separate posts). Eryk's midrange spec alone invalidates Khesin's claim (never mind that the Rethm Saadhana DX55 covers 75Hz - 20kHz, Zu's widebander 40Hz - 12kHz for just two additional and easy examples in my stable). At 200Hz, the Ketsu S' third-order low-pass hands over to two paralleled 150mm/6" woofers in a single bass-reflex chamber. This smartly limits LF extension of the puny widebanders to avoid overdrive distortion.


If you want "more pure diamond and gold than you'll find in any $500,000 diamond engagement ring", the Ketsu S won't oblige with even a glimmer. The Polymer Logic will. Of course you'll first have to agree with the implied premise that rock-hard synthetic diamond makes for the most desirable midrange diaphragm extant. The Eryk Ketsu Supreme, a tricked-out version of the standard Ketsu, brandishes mere paper. There are no hi-tech bragging rights. Sniff. Alas, there is that €3,700 invoice. Some could feel it makes up?


This detour into polymer logic wasn't to diss an expensive speaker. I haven't heard it. It was simply to make two points. One, much of modern hifi marketing rides the hi-tech material train for speakers - Beryllium, synthetic diamond, Carbon, Kevlar, Magnesium. Claims for superior specs notwithstanding, how do such materials correlate with sonics? Two, wide midrange bandwidth remains a worthy goal not just for the usual suspects - Fostex, Jordan, Lowther, PHY, Supravox and Co. Even a company marketing modernity can agree that not to splice in a driver smack in the presence region is desirable. As Daniel Khesin put it, "even the most brilliant engineers cannot successfully place a crossover at 1300Hz and make it invisible to the ear." To avoid that needn't cost $25,000 nor use diamond drivers.


To this day, sadly no single dynamic driver will cover sufficient bandwidth to believably present especially modern music with its powerful bass (some might say Baroque is fine). A large-diameter widebander still needs help in the treble, a small one in the bass. Yet even a widebander 2-way will suffer intermodulation distortion when simultaneous infrasonics and vocal-band data coincide on one cone. Unless your widebander sports exceptional treble reach to eliminate the need for an add-on tweeter, a three-way seems nearly mandatory to liberate your widebander from undue breakup at the edges. Hence Tommy Hørning walks this path. So does Zu Audio with its bigger Presence and Definition models. WLM does with its actively driven subwoofers and two-ways. Now add Eryk S Concept with its Ketsu and Ketsu S.
Where Eryk Smólski differs from the cited wideband companies is in voltage sensitivity. The Ketsu S is a conventional 88dB. Asked why not higher, Eryk Smólski explained that "high sensitivity is always one of the goals but when you pursue linear response and light and quick membrane response, coming in above 90dB is mostly wishful thinking. More important to us was wide bandwidth. With drivers over 10cm/4", this is almost impossible to attain due to obvious physical rules or else one ends up with certain nonlinear distortions. Usually, full bandwidth is obtained with 5 to 8cm (2" to 3") drivers. Modern variants are now capable of high power handling at average sensitivity ratings. To obtain higher efficiencies means horn-loading or higher diameter drivers which changes dispersion, introduces colorations and necessitates a broad 'old school' type cabinet."
His petite cabinet structure of 13 x 35 x 98cm WxDxH (5.1 x 13.8 x 38 inches) is a mix of 20 - 40mm/0.8 - 1.6" MDF panels. Over the standard
€2,600/pr Ketsu, there's "improved internal bracing and a new connecting system for the front and rear panels. The double-drive woofers are adjusted to operate with minimum time delay, speed and accuracy in a small chamber. Strong vented magnets couple to CCAW-wired aluminum voice coils and lightweight 10g membranes. Triple damping here includes bitumen mats, pyramid foam and low-density material. The broadband drivers work in a closed chamber damped with wool fiber. The super tweeter uses a neodymium motor. Besides working as frequency optimizer, the crossover network also stabilizes phase and linearizes impedance (3 - 6 ohms) to present a non-reactive amplifier load. The hookup wire is silver for hot, copper for return. Power handling is 150 to 200 watts and frequency response is 31/40Hz to 22/25kHz at -6/-3dB. Our drivers are EU-sourced to our specifications. The asymmetrical rather than opposing-pair woofer array creates more in-room flexibility by offering woofers in/out placement. As you noted, the S-version went from the former sealed to a bass reflex alignment. This was chosen to extend bass reach, amplitude and efficiency. To net the same speed and impulse response as in a sealed enclosure, with light rather than common and sluggish 50g membranes altering the T/S parameters, was a real challenge." This statement was followed by a smiley face. It indicated both modesty and pride over a hard-earned personal achievement.

This speaker sells factory-direct through Eryk's on-line store but also enjoys US and Dutch affiliates at Decibel Garden and East West Audio respectively to shorten shipping distances for American and Western European customers. The opening photo montage around the standard Ketsu shows a very small sampling of available finishes. Each pair of Ketsu S is built to order in a custom finish -- the stated price includes that -- and delivered after 6 weeks. Warranty is two years. The apparently Asian company logo combines ancient Tartar symbols with a Japanese flair to imply precision quality. On paper and purely conceptually, the Ketsu S with its super-narrow profile combines widebander appeal with a realistic assessment of one/two-way intermodulation effects. Then its voltage sensitivity adds inbuilt suitability for normal amps. Lowthers for Brystons? My upcoming audition with Coda's beastly 450-watt CX monos and Abbingdon Music Research's massive AM-77 integrated should determine that. For now, it's certainly an uncommon notion. Add a fair price for what bills itself a high-performance ultra compact tower. Has 40-20,000Hz widebander appeal just found an unlikely but interesting new champion?

Good impressions begin the moment the four-handled MDF crate arrives. It continues when you unscrew hex screws which are far less prone to stripping than Philips heads. Then you discover their steep thread, meaning they come out rapidly. If you don't think such mini details matter, think again. If someone pays attention to this stuff, he pays equal attention to everything else. No surprise then that the speakers were shrink-wrapped to protect their gorgeous ivory lacquer and deep-gloss Rosewood trim.
"These are the most beautiful speakers you've ever received." That was the wife speaking. I couldn't disagree either. The width of a CD case, in gorgeous two-tone with unusual L motif (back and integral plinth in veneer), grooving of the side panels creating more visual interest, plus the sheer level of fit 'n' finish... all this spoke of - well, bespoke goods.

Removing the grill, you notice two clever details: The grill is tension-fitted to leave no connector holes when removed; and the inside of its frame is lined with a dense foam strip to absorb edge reflections. I've seen $10,000/pr+ speakers that forgot about this aspect.


Smarts continue 'round back. The defeatable bullet tweeter sports bridged terminals. A single jumper from the main hot terminal to the lower ST post will get it going, no added jumper leaves it out of the circuit. Needless to say, eight spikes and matching floor protectors are also included.

The side-firing woofers come uncovered but their mounting screws are copper-colored for a subtle visual accent. The trim rings sport Dual Drive Concept engravings for another touch of class.


Ditto for the cosmetics of going without the front grills. The mount screws are copper colored and the driver baskets are hidden between a trim plate. Another engraving separates the two widebanders.


There's even a miniature "ST" plaque on the super tweeter grill and an ST Connector engraving on its bridging strap.


With the grills in place -- a tasteful grey with my loaners -- the only decal in sight is a mute silver plaque with Eryk's logo.


While fashion designers would instantly recognize the usual branding tricks, how they've been implemented here is exceptionally classy.


Accordingly, don't expect a tacky paper sticker with a hand-written serial number on the back neither. It's another fully engraved plate below the widely spaced 5-way binding posts. The upper of the two back-firing ports is plugged with foam for resistive loading when delivered, the lower remains open.

Naturally, the upper foam plug is easily removed to adapt the bass alignment tuning to the room. The speaker is ultra narrow and there are no outriggers to broaden its stance. For non-canine, non-toddler households, I don't see any issue. In fact, I much prefer the elegant slim footprint as is. However, households with much careless foot traffic should be alert that bumping this speaker will far more easily topple it than the usual chunky behemoths.


After-market outriggers are available whose mounting channels will accept any spike bolt spacing extant and attach securely to even as narrow a speaker as the Ketsu Superb.


After this obligatory inspection, I had to, hand on heart and no lie, scroll back up to the top of this page and remind myself of the pricing. €3,700/pr! Americans with the currently limping dollar will be less impressed of course but as someone back in Europe to now think € rather than $, Eryk S Concept offers a ton. Remember the custom finishes. Anything goes. I had no idea what Eryk Smólski would supply for this review pair but based on his choice and execution, I fail to see how anyone could be disappointed by the coin-for-cosmetics factor on tap here. Cheers.

Audiophiles, we're told, are devoutly immune to any such charms. All they care about are sonics, looks be damned. With damnation already handled with such aplomb, we can pursue more sinful stuff sans further punishment next...