Reviewer: Srajan Ebaen
Financial interests: click here
Sources: Retina 5K 27" iMac (4GHz quad-core with Turbo boost, 32GB RAM, 3TB FusionDrive, OSX Yosemite. iTunes 12.2), PureMusic 2.04, Qobuz Hifi, Tidal Hifi, Fore Audio DAISy 1, COS Engineering D1, Metrum Hex, AURALiC Vega, Aqua Hifi La Scala MkII, SOtM dX-USB HD w. super-clock upgrade & mBPS-d2s, Apple iPod Classic 160GB (AIFF), Astell& Kern AK100 modified by Red Wine Audio, Cambridge Audio iD100, Pro-Ject Dock Box S Digital, Pure i20, S.A. Lab Lilt [on loan]
Preamplifier: COS Engineering D1, Nagra Jazz, Esoteric C-03, Vinnie Rossi LIO with AVC
Power & integrated amplifiers: Pass Labs XA30.8, FirstWatt S1, F6; Crayon Audio CFA-1.2; Goldmund Job 225; Gato Audio DIA-250; Aura Note Premier; Wyred4Sound mINT; Vinnie Rossie Lio; AURALiC Merak [on loan]
Loudspeakers: Albedo Audio Aptica; EnigmAcoustics Mythology 1; soundkaos Wave 40; Boenicke Audio W5se; Zu Audio Submission; German Physiks HRS-120, Gallo Strada II w. TR-3D subwoofer, Sounddeco Sigma 2
Cables: Complete loom of Zu Event MkI and MkII; KingRex uArt double-header USB; Tombo Trøn S/PDIF; van den Hul AES/EBU; AudioQuest Diamond glass-fibre Toslink; Arkana Research XLR/RCA and speaker cables [on loan]
Power delivery: Vibex Granada/Alhambra on all components, 5m cords to amp/s and subwoofer
Equipment rack: Artesania Audio Exoteryc double-wide 3-tier with optional glass shelves and Krion or glass-based Exoteryc stand/s for amp/s
Sundry accessories: Acoustic System resonators
Room: Irregularly shaped 9.5 x 10m open floor plan with additional 2nd-floor loft; wood-paneled sloping ceiling; parquet flooring; lots of non-parallel surfaces (pictorial tour here)
Review component retail:
€29'900 with AC-4x (standard Ampeggio) driver; €34'900 with AC-4d driver (higher efficiency/resolution), €4'900 surcharge for field-coil driver with power supply; €17'900 for just the active subwoofers

9.87 system at Munich HighEnd 2015, bass modules shown in pre-production flat paint which became matching gloss in production.

What if. That's how many a good yarn begins. So let's. Begin. What if one could square the Life of Pi? it'd be one helluva movie. Or book since that came first. For Berlin firm Voxativ, the squaring of the pi arrived at Munich HighEnd 2015 with the 9.87 system which—rekindle your foggy math skills—is 3.14159. x 3.14159 = 9.8695877281. Multiply a number by itself. That's called squaring it. 2² = 4, 3² = 9 and so forth. Here 3.14 of course is that famed endless number π. It determines the ratio of a circle's circumference to its diameter. Unlike the movie's character Piscine Molitor Patel of Pondicherry/India, Pi in Voxativ's catalogue is their entry-level wideband monitor with integral rear-horn loading. Squaring it now with an active bass system is Holger Adler's materialized admission: even the very best widebander—and his belong to the crème de la crème for a fluffy squaring—doesn't make 20Hz or even 30Hz or 40Hz like a specialized dynamic woofer can, mega mondo maxi rear-horn loading notwithstanding. He'd probably disagree with that last part given how the top Voxativ Ampeggio Dué is spec'd to go the full hog. But having in 2010 reviewed, awarded and subsequently owned the smaller Voxativ which afterwards also made Stereophile's Product of the Year; and having since lived with a variety of mostly smaller 2-way towers or monitors plus Zu Audio's tall Zu Submission infra sub... I'll agree to disagree. I'm firmly of the belief that sub 40Hz assist for a superior widebander which already hits an honest 20kHz on the other end is not only kosher and performance enhancing. It's zero cause for shame or expulsion from the widebander religion. It simply bites back at reality. Here it's only the unreasonable idealist of purely abstract concepts who'd snarl at the notion of augmenting a stonkin' 9-octave transducer for the 20-40Hz band. That's especially apt if one, as does Holger, mates one's 99dB widebander with a big woofer of matching efficiency, no power conversion trickery involved to artificially inflate that figure.

To put that pretty purity pox in another light... even if the far bigger speaker in the above photo could make identical bass on quality and quantity, wouldn't you rather own the smaller stack?

I'd propose that's a giantific 'if' to begin with. The simple reason? The Dué lacks the adjustments of the Pi's active bass system. The next show photo tells that story in a 1'000 words.

Finally, the Dué is wickedly more expensive than the squared Pi. And since we're still in follow-on Munich mode, another thing. For a few years and quite surprising when it first occurred there and elsewhere, one could hear Holger's Voxativ drivers in the Voxativ exhibit plus the Jo Sound exhibit. In fact, more than once these two competing brands co-exhibited in the same room. They simply occupied different walls and turned the seats in the respective direction of whatever was on active demo at the moment. This year's visit to Jo Sound spelled AER drivers instead. A quick question settled it. The companies' owners had parted ways to leave Voxativ as the currently only production brand to sport Voxativ drivers. Exclusivity!

Back to subwoofer-augmented widebanders. The traditional resolve against them was speed. Or rather, the lack thereof. If a widebander hits 100dB efficiency, traditional subwoofers tend to hover in the 88dB region. They were never particularly designed to mate to high-efficiency speed freaks. As such, they mostly pursue long-throw woofers with massive rubber-roll surrounds. Meanwhile a wideband Lowther is limited to ±1mm travel. It's easy to spot a discontinuity of mechanical operating systems. As owners of Avantgarde Acoustics spherical hornspeakers know all too well—I used to run Duos—they suffer the exact same dichotomy. For them it's easy does it on top. Here hornloading adds an 8-fold increase of acoustic energy to the signal delivered to the voice coils. Meanwhile a sealed dual-woofer bass system relies on the brute force of high-power transistor amps. Disguising that seam of opposing principles relies on expert setup. Some think it can never be erased entirely.

Jacob George of Indian speaker house Rethm struggled for ten long years with the low-bass limitations of single-driver designs. Finally he began to incorporate self-powered isobaric woofers of the same diameter as his widebanders. With the 9.87 system, Voxativ have now arrived at the same juncture. They've addressed their own displeasure at conventional subwoofers head on. Holger's particular answer? Class A/B not D for the 250-watt muscle; and a folded open baffle called H-frame to eliminate box talk and exploit directional dipole cancellation for lesser room-mode activation. Again, it's about 'fast' bass of the same texture and lucidity as the widebander's colossal hence seamless bandwidth. For the real story behind this sketchy story, let's turn to Holger on the genesis of the 9.87 project and its final realization.