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Reviewer: Srajan Ebaen
Financial Interests: click here
Source: Esoteric UX-1, Yamamoto YDA-01, April Music Stello CDT 100|DA100 Signature
Preamp/Integrated: Esoteric C-03 (transistor), ModWright DM 36.5 (valves), Luxman SQ-38u [on review]
Amplifier: Yamamoto A-09S, FirstWAtt F5, ModWright KWA-150, Octave MRE-130 monos
Speakers: ASI Tango R, Zu Essence
Headphones: Audio-Technica WHT-1000, Beyer Dynamic DT880
Cables: Complete loom of ASI Liveline
Stands: 4 x Ikea Molger and butcher-block platforms with metal footers
Powerline conditioning: 2 x Walker Audio Velocitor S
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: $1,360 for heavy turntable shelf or dedicated amp stand; $2,720 for 2-tier rack, $3,400 for 3 tiers, $4,250 for 4 tiers


What can be said about an audio rack? Actually quite a bit. The most obvious—bit—is that a rack houses multiple components. As such, it's significantly bigger than any of them. You better love the way it looks. In the end, it's a piece of furniture. And besides expense, for some that's indeed the main focus. Owning piles of hifi kit in need of being stashed away neatly, such folks rightly wonder. Why should their type of basic functional necessity cost high-end prices? Fair and square enough. Ikea could have your solution; or perhaps a bona fide furniture maker. Glass doors allow infra-red signal to pass so you needn't completely see your equipment to operate it remotely.

For other audio pilgrims however, there's the tantalizing promise of extra performance. They hope for sonic improvements bestowed upon their audio components by the plain and simple virtue of being housed on a special kind of rack. Pure utility expands to sonic upgrades. An audio rack becomes an active component of sorts. It's all within a day's work for anyone who seriously considers the implications of sound as energy. This energy transmits through the air to impact apparently solid objects that share the same air space. The air disturbances are of course generated by our loudspeakers. Particularly full-range ones played back at high levels send powerful bass pulses not only into the air but, like jack hammers, into the floor. There these pulses propagate. Among other places, they migrate into the audio rack which—unless wall-mounted—stands on the floor to become a coupled recipient. (This is why decoupling audio racks and speakers from the floor can have very audible benefits. It undermines opening the floor to the Resonant Exchange® traders, pun intended).
Within the category of performance-enhancing audio racks, there are two sub categories. The first includes all broad-band resonance attenuators which are subtractive in effect to work the same regardless of what components you put on them. The second includes structural tuning devices which by addition or selective shifting of resonances alter the sound in deliberate ways that please the right listener with the right equipment. Brands in the first category include Finite Elemente, Grand Prix Audio, HRS and Silent Running.

Franck Tchang's ASI HeartSong rack belongs into the second category. Ditto Combak / Harmonix and Yamamoto SoundCraft. The ASI rack exploits very specific hardwood species—Yellow Heart for shelving, Purple Heart for the frame, Brazilian Rosewood for frame/shelf couplers—and is said to avoid metal screws, bolts or similar fasteners.

For a conceptual tie-in, consider clarinets which can be crafted from African Grenadille Blackwood, Mopane and Ebony. Certain very early specimens were made from Buxbaum. Each wood creates a different sound for the instrument which is crafted from it. Bass clarinets come with upward-curved bells and S-shaped necks. Due to their bent shapes, those sections tend to be metal. However, some clarinetists claim the metal bits in the resonating air stream diminish the sound and prefer wooden end bells and straight but angled necks. They would positively plotz at the kind of all-metal clarinets popular with certain Turkish gypsies.


That different woods would have strong bearings on musical instruments is a mundane fact to musicians. They wouldn't dream of plastic or carbon fiber substitutes. Translating this to a hifi rack however isn't straightforward. There the individual qualities of particular woods are supposed to be universally beneficial. Success for Mr. Tchang's rack—and others which are based on similar tuning principles—depends on which additive traits were strategically 'built in' and at what potency. Unlike subtractive racks which must apply significant damping since their goal is a wholesale suppression of resonances, additive racks amplify certain vibratory actions. This sets up a deliberate harmonic convergence effect over specific narrow bands in the audible range.

Their interaction with components which suffer diverse shortcomings ought to be rather less predictable than the subtractive approach. Nearly by definition, the second approach defies a rack's potential to become a universal panacea. What if it fattened up tone but that was the last thing your particular system needed? Interestingly, most racks in this second category rely on solid wood whereas the first category tends to prefer complex composites, constrained layers and metals. Different tools for different jobs. Another conceptual watershed exists between rigid high-mass constructions and freedom-of-motion low-mass designs. This has parallels to loudspeaker enclosure design where some opt for thick-walled inertness, others for very lossy undamped thin walls.