Stack attack on the rack

Reviewer: Srajan Ebaen
Financial interests: click here
Main system: Sources: Retina 5K 27" iMac (i5, 256GB SSD, 40GB RAM, Sonoma 14), 4TB external SSD with Thunderbolt 3, Audirvana Studio, Qobuz Sublime, Singxer SU-6 USB bridge, LHY Audio SW-8 & SW-6 switch, Laiv Audio Harmony and Sonnet Pasithea; Active filter: Lifesaver Audio Gradient Box 2; Power amplifiers: Kinki Studio EX-B7 monos & Gold Note monos on subwoofer; Headamp: Kinki Studio THR-1, Enleum AMP-23R, aune S17Pro Evo; Phones: Raal 1995 Immanis; Loudspeakers: Qualio IQ [on loan] Cables: Kinki Studio Fire, Furutech; Power delivery: Kinki/Vinshine Tai Hang on amps, Furutech GTO 2D NCF on low-level gear; Equipment rack: Artesanía Audio Exoteryc double-wide 3-tier with optional glass shelves, Exoteryc amp stands; Sundry accessories: Acoustic System resonators, LessLoss Firewall for loudspeakers, Furutech NCF Signal Boosters; Room: 6 x 8m with open door behind listening seat; Room treatment: 2 x PSI Audio AVAA C214 active bass traps
2nd system: Source: FiiO R7 into Soundaware D300Ref SD transport to COS Engineering D1 DAC/pre; Filter: Lifesaver Audio Gradient Box 2; Amplifier: Kinki Studio EX-M7; Headamp: Cen.Grand Silver Fox; Loudspeakers: MonAcoustic SuperMon Mini + Dynaudio S18 sub, sound|kaos Vox 3awf, Albedo Aptica; Power delivery: Vibex Granada/Alhambra, Akiko Audio Corelli; Equipment rack: Hifistay Mythology Transform X-Frame [on extended loan]; Sundry accessories: Audioquest Fog Lifters; Furutech NFC Clear Lines; Room: ~3.5 x 8m
Desktop system: Source: HP Z2 work station Win10/64; USB bridge: Singxer SU-2; DAC: iFi Pro iDSD Signature; Speakers: DMAX P61; Headphones: Final D-8000 & aune SR7000 Audeze LCD-XC
Upstairs headfi system: FiiO R7; Headphones: Meze 109 Pro, Fiio FT3, Raal 1995 Magna, HiFiMan Susvara
2-channel video system: Source: Oppo BDP-105; All-in-One: Gold Note IS-1000 Deluxe; Loudspeakers: Zu Soul VI; Subwoofer: Zu Submission; Power delivery: Furutech eTP-8, Room: ~6x4m
Review component retail: ~€1'135/6 contingent on the day's £⇒€ exchange rate

This is compact companion commentary to my prior Auva 70 review. If brevity is the soul of wit, double-dipping is the whole kit? It's not just verbal silliness pickled in rhyme brine. Today looks at the floor/rack interface which effectively isolates—or doesn't—all components housed on said rack. Floor-borne mechanical resonance from the invisible jackhammer action of loudspeakers and subwoofers is the gravest enemy of structural silence. Anything sharing the floor with our transducing exciters is apt to absorb their migrating vibrations. Hence the first line of defence gets our speakers off the floor. We disrupt their mechanical transfer of unwanted vibrations. Done! If our choice of speaker isolator is 100% effective, nothing else should need doing on that score. Time to head to Zakynthos for some fun in the sun. If our scheme leaks like a dripping faucet for some Chinese water torture? Add isolation between rack legs and floor. Unlike dripping water, we likely can't tell whether our speaker isolators leak until our rack is off the floor, too. Does that make a difference? If not, our curiosity backfired. Time to invoke that return privilege. As a reviewer, that's always implied. Stuff goes back whence it came unless I buy it or get a long-term mutually beneficial loan. When Stack Audio's Josh Stephenson asked whether my systems had any remaining 'holes' their particle-damping tech might seal off, I suggested my very heavy Artesanía double-wide Exoteryc rack on its stock very basic six spiked shoes.

Auva 70 beneath the Qualio IQ speakers, basic knuckle-joint spikes and large floor-protector discs beneath equipment rack.

That memo Josh had already gotten: "I'd be very happy to get some units to you to try under your rack. This approach we have taken in our office setup since Auva inception and many clients started to take in recent months. Isolating a rack is vital to negate any remaining floor-borne vibration and protect our equipment." Just how many vitamins of that vital might I ingest when my 2×15" sub already floats on sound|kaos Vibra 68 triple-wire suspenders, my Qualio IQ speakers on just-acquired Auva 70? That was my question. Doing the deed would mean emptying the rack of all kit and its cable kaboodle to flip upside down on the carpet and swap footers without marring the parquet floor in the process. There'd be no lazy man's way out of this enheaviment. But reviewers are supposed to work for a living. Opinions not backed by actual experience are another gig entirely. So I signed up. Did my curiosity write a check my ears and back wouldn't cash? "Your honour, I put it in the mail. I swear." Josh certainly upheld his end. A sextet of their Auva 100 dispatched by overnight DHL I expected a long weekend of blood, swears and tears.

Here's my after. Audio's après ski, cognac in hand, feet toward a roaring wood fire? Not in Eire. Not in early June. Here it's whiskey and propane heaters. But calmer heads had to prevail, observational sobriety intact. Did anything call my attention other than a slightly altered appearance and minor height gain? Just like on Artesanía's slippery white nylon discs, the entire rack easily slid toward my rug for rear access during rewiring. I pity those with plush carpets whose stationary racks demand permanent wall clearance; or yogic contortions. I could easily jam my double-wide structure against the wall for normal use then pull it out a fat metre when needed. Zero scuff marks. Little things make or break a deal. On convenience and unshakable solidity, I was made. Ditto for finally being able to lift the rack without losing its lower footer halves as I did with the two-part stockers. Though I haven't a sword, I was quite prepared to fall on it and declare naught else. After all, this Spanish multi-stage rack already aces isolation. How much more was feasible? And, just how fussy would my bloody digital have to be to even notice? Much to my surprise, the difference wasn't subtle. It was of tone, not tonality. In my vocabulary, the latter is a function of tonal balance. There—so quite unlike with my prior speaker/sub isolation experiments—nothing budged. Neither did I hear increased treble clarity or soundstage depth. This change was all about tone yet not from more obvious harmonics. With overtones, I'd invoke timbre not tone. My best pointer for this tone difference is adjustable negative feedback. If you've played with that parameter usually on valve amps, you know how more feedback dries out tone and how none tends to sound juiciest. Unlike with valve amps however, this quasi reverb assist came without their temporal blur. I got a version of their dialled-back NFB tone enhancement which wasn't octave-doubled 2nd-order saturation nor did it cause textural changes. I just haven't the Irish foggiest how and why this came about. No matter. Like a thief in the night, I grabbed my shiny loot and took off before the audiophile police arrived.

In the foreground two of Artesanía's stock floor couplers. For a different tuning they also offer softer neoprene inserts as used under the triple tempered-glass turntable shelf.

Knowing my system intimately whilst playing familiar tunes, this result was plain. I needed no accepted or imaginary explanation to share it. Having experimented with Artesanía's neoprene and nylon inserts in their footers when I first acquired the rack; and later replaced their plastic/neoprene component interfaces with the beech version – I know how different materials contribute their own 'sound'. Sven Boenicke once joked that because our human body consists of it, bone would make the best speaker cabs. Aavik are adamant that Titanium and copper sound better than aluminium. The late Eduardo de Lima of Audiopax compared steel, aluminium and bronze enclosures for his amp and stated a clear preference for bronze. This he finished in non-corrosive chrome. I doubt that different materials alone explain what I heard. But might they have contributed? Again, just how fussy must digital circuits be to respond to some possibly just fractional reduction of floor-borne vibrations which were already effectively minimized to start with? Thankfully my job isn't to provide answers but observations. I promised compact commentary so here it is.

Stack's rack attack was a hack on personal expectations yet clear track to more beautiful inner light of tone. Will a hard tile or stone floor change where and how sonic changes manifest? That'll be for others to report who have such floors. For now I'm on real-wood parquet with wooden subfloor. Very much contrary to anticipation, this is what I heard. It goes to show that once our system resolution is sufficiently purified, our listening keen enough, interesting discoveries await on how our structural support choices—racks, plinths, shelves, footers, spikes—and their material makeup and MO interact with our hardware and environment to flavour the sound. Garrard 301 restorers with custom plinths know all about that.

I really dug what six Auva 100 moons with M10 thread adapters did for my domestic flava. Thanks to Stack for indulging my curiosity. Clearly many of their clients are already well ahead of my late isolate-yer-rack awakening. It begs a final thought. Performance-engineered racks from Artesanía to Hifistay and HRS are costly, heavy and industrial. It's long been my contention which finds itself reiterated by today's experiment. The primary job of a proper rack is to isolate our kit from the floor not each other. A set of Auva 100, 70 or 50 terminating a cost-effective bamboo shelf stack with more furniture than lab appeal should mod it into a real performance rack for pretty pennies on the portentous pound. You'll save coin and safeguard your domestic bliss. If today's tiny tale inspired you but the look or cost of my rack did not, consider combining Auva with furniture you love. Why couldn't you have both isolation performance and cosmetics that suit?

Doing a quick 'n' dirty on Amazon.ie took 30 seconds to scare up this €541 wheeled bamboo job. One might have to drill threaded inserts to bolt to Auva not just sit on it so pass. Yet the point is made. With a bit of recon, it shouldn't be hard to mock up a serious performance rack that doesn't look like one. Might that not be just the ticket to have your gateau and gorge on it, too? To really goose that gobbling, you could always add isolators beneath a vibration empath turntable or CDT which might benefit from still more pampering, princess-on-her-peas style. As it happens (cough), Theo Stack also has something for such apps. It's the Auva EQ. But in my book, the smart-money sequence attacks structural resonances first at our speakers and subs. If more vibe vanquishing remains, next get the rack off the floor. Floating individual kit on already floor-isolated shelves should be the final straw; if it even slurps then. Either way, cheers.

PS: By August I'd come across and bought this €129 4-tier FituEyes Eiffel rack then replaced its threaded rubber bumpers with performance-engineering hifi isolators. I had a spare quad of sound|kaos wire-suspension footers. Stack Audio Auva would obviously work just as well.