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Srajan Ebaen
Financial Interests: click here
Source: 1TB iMac (AIFF) via FireWire into Weiss DAC2
Preamplifier: Esoteric C-03
Amplifier: FirstWatt F5, J2 and M2 [on review], Trafomatic Audio Kaivalya monos, Yamamoto A-09S
ASI Tango R, Zu Essence
Cables: ASI Liveline
Stands: 2 x ASI HeartSong 3-tier, 2 x ASI HeartSong amp stand
Powerline conditioning: 1 x Walker Audio Velocitor S, 1 x Furutech RTP6
Sundry accessories:
Furutech RD-2 CD demagnetizer; Nanotech Nespa Pro; extensive use of Acoustic System Resonators, noise filters and phase inverters, Advanced Acoustics Orbis Wall & Corner units
Room size: The sound platform is 3 x 4.5m with a 2-story slanted ceiling above; four steps below continue into an 8m long combined open kitchen, dining room and office, an area which widens to 5.2m with a 2.8m ceiling; the sound platform space is open to a 2nd story landing and, via spiral stair case, to a 3rd-floor studio; concrete floor, concrete and brick walls from a converted barn with no parallel walls nor perfect right angles; short-wall setup with speaker backs facing the 8-meter expanse and 2nd-story landing.
Review Component Retail: €16.900/pr (excl. VAT)

Loudspeaker firm Voxativ of Berlin is unusual. It's fronted by Inès Adler, a woman and accredited engineer*. That's exceedingly rare in our male-dominant sector. Next, certain of her speakers are crafted by Schimmel, a specialty German piano builder. Again there are only few precedents. For musical instrument builders turned loudspeaker makers, only Bösendorfer speakers, the Steinway project with Peter Lyngdorf and the Takamine collaborations with Onkyo and Kiso Acoustics come to mind. But there's more. Inès outfits her widebander speakers with her very own drive units.

"With respect to the old Voigt, Jensen and Klangfilm drivers, this type of transducer has now been revived with new technology and materials. Our suspensions are made from genuine goat leather to save a lot of motional cone energy which suddenly becomes available for music reproduction. The result is incredible detail resolution. Our top AC-X is driven by a large field coil instead of permanent magnet. With this magnetic force, the driver reaches maximum dynamic performance. Its housing is made from carbon-free steel and additional Permendur plates. The AC-X has a Qts between 0.25 and 0.6 contingent on the supply voltage which can be set from 6 to 18 volts. That enables the user to adjust the driver to all installation conditions and playback requirements.


* Initially just as a hobby, Inès Adler began experimenting with widebanders in the 1980s. After she finished her engineering studies with a master's degree, she went to work for Daimler's Mercedes Benz diesel section where she developed engine electronics, ECUs and software. She holds 14 patents on diesel combustion, injection and exhaust treatments. In the late 90s Inès wanted to optimize her widebanders and began a second round of many experiments which netted promising results. To properly distinguish her Voxativ drivers from all precursors like Lowther, AER, Stamm and Loth-X, she designs and fabricates each component part from scratch.

Ampeggio with black goat leather surround
"Back to the AC-X and different to the designs of the 1940s or current DIY projects, its field coil is completely shielded to avoid field radiation and increase performance. The reduction in supply voltage of the approximately 100V in vintage designs to now 12V and a maximum of 18V has the AC-X conform to all modern security and energy conservation issues. Enclosure options include full-range mode in a back-loaded horn for bass radiation to 25Hz; open baffle (plans are delivered with the driver); and as 2-way freely radiating driver with dipole woofers or loaded into a front horn."

The specifications for that particular** Voxativ follow. Bandwidth of 20Hz - 20kHz. Max sensitivity of 108dB. 50-watt nominal power handling. Impedance R 10.7Ω. Complex impedance Z 16Ω. Resonant frequency 29.12Hz. Qms 3.1/12V. Qes 0.4/12V. Qts 0.354/12V. VAS 148 ltr. Xmas 8mm. Depth 166mm. Installation diameter 190mm. Weight 12kg. For context, Lowther's EX and DX Series drivers have an Xmas of 1mm and a weight of 3 - 4kg. Lowther's big PM-4 has a free-air resonance of 70Hz as do most Lowthers. The math becomes predictive. The Voxativ unit should be unusually broad of bandwidth and output.

What Inès suggested for review was her Voxativ Ampeggio speaker which she'd shown at the Munich High-End show earlier this year together with Schimmel Pianos (intro image).

** The AC-X [€4.620/pr excl. VAT] comes standard with an SMPS. A transformer-based power supply adds €415, a battery power supply €2.269. In each case, the supply is fixed at 12V. The Voxativ driver range begins with the AC-1 at €1,099/pr excl. VAT and tops out with the AC-X. The AC-3X as second from the top is tuned especially for the Ampeggio model. It costs €3.696/pr excl. VAT. Compared to the company's AC-3B unit which has a moving mass of 6 grams and a magnetic force of 2.1 Tesla, the AC-3X reduces moving mass to 5.5 grams and increases magnet power to 2.3 Tesla." 

The Ampeggio's driver really is the Neodymium version of the AC-X and loaded into a back-horn enclosure which is made from tone wood with facetted turns to precisely control internal reflections and resonances. This enclosure is then covered in 1mm deep polyurethane paint that's been polished about 10 times. The Voxativ by Schimmel Piano logo is made from brass and inlaid into the paint. Hookup wiring is solid-core copper, the solid-copper binding posts are Mundorf issue. "The system's efficiency is 98dB to pose no problems for small luxury amps like Yamamoto." The Ampeggio measures 40 x 110 x 35cm WxHxD and weighs 55kg. Finish options for the Schimmel version are piano gloss black and white, otherwise gray or Cherry veneer. Frequency response is a claimed 38Hz to 20kHz for realistic bandwidth at least on paper.
Tan goat leather suspension is impregnated with silicon compound to never dry out and be impervious to rot unlike foam surrounds.

"For us the partnership with Schimmel Pianos is very fortuitous. After all, they have 125 years of not just world-class woodworking experience but first-hand constant exposure to live sound. That puts them above most consumers and hifi manufacturers and on equal footing with perhaps only recording industry professionals. Their CEO Mr. Schimmel-Vogel is a very nice gentleman who was looking to partner with a speaker company. He chose Voxativ because the sound of our speakers was closer to that of a live piano than he'd ever heard before - anywhere. Further collaborations with Schimmel are planned of course and our full branding for the Ampeggio project is Voxativ by Schimmel Pianos. This properly identifies their cabinet fabrication contribution including their state-of-the-art lacquer finish. The Ampeggio driver uses a N56H Neodymium motor with double-sided copper voice coil, Kapton former, a die-cast aluminum basket and a pure calligraphy paper diaphragm that's been coated with four layers of lacquer proprietary to us. Not one part of this driver is shared with anyone else."

No matter their cost, the small print beneath unassisted widebanders states that they beam as the main driver veers into higher frequencies; are prone to intermodulation distortion since the same driver handles low bass, midrange and treble (whether that's practically audible is another matter); suffer limited bass dynamics because diameter and stroke can't be optimized for LF; tend to suffer a presence region lift and other response irregularities; usually aren't as treble extended as dedicated tiny tweeters; and when of high efficiency, use very light thin cones which further undermine high-output low bass.

On the bonus ledger, there are no energy-robbing passive crossovers with their phase shifts and time-domain problems; no multi-driver integration issues; high soundstage precision from point-source radiation; and particularly with high-sensitivity variants, good nuance retrieval at even low playback levels and the ability to be run with low-power purist amps. When such widebanders increase in cost as does the Ampeggio, the onus on serious dominance—of plus over minus—becomes potent. That's particularly so once we consider (and compare against) a multi-driver design like my closely priced ASI Tango R. On the face of it, could one driver even hope to compete against five, three of which are dedicated to bass alone? Those subscribed to the ongoing allure of the breed naturally believe that yes, it can. Those with a more realistic attitude would add, where it most matters.

The paper diaphragm is sealed with 4 coats of lacquer on each side
to prevent moisture absorption and rot in any climate.
This review will answer what most in this context means. And whether, for once in this sector, it even has to be a qualifier as it most certainly does with Lowther and Feastrex. With Inès delivering to ascertain that my space and ancillaries were up to snuff before leaving a loaner pair in Casa Chardonne, we jointly agreed. My Trafomatic Audio Kaivalya monos were the absolutely perfect match followed by FirstWatt's M2. The Yamamoto A-09S wasn't quite dynamic and controlled enough, the F5 too lit up and tonally a tad lean. The J2 was better but on transistors, the M2 took the cake. The EL84s then added tone density and elegance.

Once toed in at the recommended 18°, Inès pronounced the performance in my room superior to what she gets in her own 300m² space - except that she called my lack of front-wall reinforcement audible in the Ampeggio's bottom octave weight. No surprise there.

What was shocking is that I still had solid snappy bass to 40Hz despite this unconventional and basically counter-productive placement. Most commercial Feastrex, Lowther, Jordan and Fostex offerings I know would kill for such extension run solo under these conditions. While PHY surely has it, their big driver doesn't make it past 10kHz to enforce a separate tweeter. The Voxativ AC-3X clearly required no auxiliary tweeter or woofer. Had I finally encountered a driver which truly lived up to its billing as widebander or fullranger?