Selecting an audiophile equipment rack can be unnerving. Rack makers rarely agree on anything, and almost all assert that their chosen design is the best. Look, for example, at the bewildering number of construction materials used: aluminum, acrylic, carbon fiber, ceramics, glass, granite, steel, and untold numbers of woods, common and exotic, solid and composite -- to name just a few.

Then there’s the cost. The price of a rack can be astronomical, and it’s an expense that typically comes after you’ve already blown your wad on electronics, speakers, and cables.

It’s at that point, often through word of mouth, that many audiophiles get in touch with Peter Bizlewicz, founder of Symposium Acoustics, a New Jersey-based manufacturer of vibration-control products. That’s what I did a number of years ago; I ended up buying two of the company’s Osiris racks.

Symposium is not a typical high-end audio company. It’s always been more about the steak (i.e., the products) than the sizzle (i.e., the marketing). It doesn’t put on flashy ad campaigns, and its website looks as if it was created from a late-1990s design template (it was). Bizlewicz is quick to tell you that his company doesn’t charge high markups on its products -- a rare and welcome practice.

Speaking of steak, many of Symposium’s products, including its racks, use its patented Rollerblock system of achieving isolation through the use of ball bearings, which Bizlewicz invented in 1997. Almost 20 years later, there is no shortage of copycat products being hawked by the company’s competitors -- a testament to the Rollerblock’s effectiveness.

Symposium Osiris

When Bizlewicz asked me to review Symposium’s new statement rack, the Osiris Stealth Ultimate ($12,500 USD), he promised that it would be a visual stunner, with mirror-finished legs of solid, oxygen-free copper (OFC) and shelves, finished in black oxide, that would represent his 25 years of experience in controlling vibrations. This rack would, he said, isolate the electronics placed on it from harmful resonances, dissipate those resonances, and provide electronic grounding and shielding from electromagnetic interference (EMI) and radio-frequency interference (RFI).

Keeping in mind Bizlewicz’s penchant for high-performing products that don’t break the bank, and wondering what the Osiris Stealth Ultimate might do for the sound of my system, I agreed to review it.

The need for speed

Most audiophiles think of resonance control in terms of isolation: preventing the transmission to audio components of external, earth- and airborne vibrations. While Symposium’s products are designed to do just that, they also address another problem that can be even more damaging to audio signals: mechanical vibrations generated within the circuits of the electronic components themselves, by their transformers, transistors, resistors, and capacitors. These vibrations are created by: 1) the pathways’ expansion due to the heat generated by electrical resistance, and their subsequent cooling; 2) unwanted magnetic and electric fields generated by vibrating wires; and 3) the moving parts in source components: transport motors, spinning discs, LPs, and hard drives.

Theoretically, one way to address components’ self-generated vibrations is through damping: the application of a material that absorbs such vibrations at their source. However, it’s impractical -- actually, impossible -- to completely damp all of a component’s internal parts. Symposium’s products are designed to do the next best thing: provide a pathway to rapidly drain mechanical energy away from the component, or dissipate it by mechanical coupling and conversion to heat. But how can a vibration-control device simultaneously isolate and couple a component?

Enter the Rollerblock, a syncretism of seemingly contradictory vibration-control theories. First used by Symposium as component and platform footers, and later in the company’s racks, the Rollerblock basically consists of a precision ball bearing resting in a cup-shaped depression machined into a rectangular block of aluminum.

When three or four Rollerblocks are placed under a component or platform -- or, in modified form, between a rack’s shelves -- they provide a hard, metal-to-metal pathway through which to conduct component-generated vibrations to ground. Also, since each Rollerblock’s ball bearing rolls in response to the displacement of the supporting surface, it simultaneously isolates the component from low-frequency lateral waves as the cup slips beneath the ball. This vibration-control methodology, known as “slip-plate technology,” is employed in the foundations of buildings to protect them from earthquakes.

Bizlewicz discovered that the more perfectly spherical the ball bearing, the more uniform its oscillations and the more isolation the Rollerblock provides. Typically, the ball bearings used in industrial and consumer products are grade 100, which means their sphericity and diameters are precise to 100 parts per million. Symposium’s entry-level Rollerblock Jr. uses chromium-steel balls specified as 25ppm: four times more precisely machined than 100ppm. Its mid-level Rollerblocks use tungsten-carbide balls of 10ppm: ten times more precise than 100ppm balls.

Symposium’s best ball bearings are 2.5ppm Superballs made of tungsten carbide, which is much harder than steel, and almost twice as dense. Bizlewicz states that though some ball-bearing manufacturers told him that 2.5ppm precision is impossible to achieve, the Superballs are quite real. They are diamond-machined in a process that takes six weeks, their precision then measured and confirmed by super-precise laser instruments.

The blocks supporting these ball bearings are made of aircraft-grade 6061 or even harder 7075 aluminum -- so-called “aircraft-grade” aluminums whose primary alloying elements are magnesium and silicon (6061) and zinc (7075). The cup is polished to an optical grade of 6µm (six millionths of a meter) or better, a standard that Bizlewicz states is necessary to reduce any surface irregularities that might impede the ball’s motion.

Bizlewicz claims that although rubber, Sorbothane, and other compliant polymers can provide some isolation, such isolation is nonlinear, and creates new distortions. Also, since these materials are far less dense than metals, their use with audio gear creates an impedance mismatch that can severely reduce or prevent the transmission of mechanical energy. Bizlewicz says that, like a rubber ball, these soft materials compress as they store energy, then expand as they release the energy. The result is that much or all of the energy is reflected back to the source, to degrade the sound.

Symposium Osiris

Which brings us to Symposium’s Osiris Stealth Ultimate, of which the Rollerblock is a key part. In Symposium’s nomenclature, Osiris means that the rack has four legs -- one more than Symposium’s Isis racks. Per Bizlewicz, the addition of the fourth leg increases rigidity and provides mechanical energy an additional path to ground. Stealth indicates that the rack’s shelves are finished in black oxide. The Osiris Ultimate is available with three, four, or five shelves, respectively priced at $11,500, $13,750, and $16,995. Adding Stealth shelves to my three-shelf review sample added $1000, to bring the total cost to $12,500. Note that these prices are for racks with all options selected. Removing one or more of the options decreases the price.

The Osiris Stealth Ultimate includes a number of technologies developed to isolate and dissipate harmful resonances:

The Rollerblock modules, rounded and resized to perfectly fit within the leg system, are Symposium’s best. Highly polished, they’re made of the very hard 7075 aluminum, and contain 2.5ppm Superballs. Further, each Rollerblock module contains a patented system of neodymium magnets that both centers the ball and reduces the ringing that occurs when it moves in the cup in response to vibrations. But the magnets are not so powerful that they hinder the ball’s rolling, and thus its isolating effect.

The Osiris Ultimates contain more Rollerblocks than Symposium’s other racks. The three-shelf Ultimate, for example, includes two levels of Rollerblocks, for a total of eight, vs. one level in the three-shelf Basic and Standard racks. According to Bizlewicz, placing Rollerblocks in series provides Symposium’s patented Compound Isolation, which greatly increases a rack’s powers of isolation.

My sample of the Osiris Stealth Ultimate included two of Symposium’s best shelves: an XTISO top shelf for critical source components, and below it, two Ultra shelves. XT, for eXtended Top, indicates that the shelf is oversize, extending slightly beyond the legs and the other shelves’ edges. ISO signifies the presence of Symposium’s Linear Displacement Suspension System (LDSS, discussed below).

The XTISO and Ultra shelves suppress resonances through the use of constrained-layer damping, a technique in which one or more distinct layers are bonded together. For the damping material, Bizlewicz uses a noncompliant closed-cell foam with a high efficiency of thermal conversion. The Standard shelf consists of one layer of this foam bonded to a single stainless-steel top sheet and a thin mediating layer. The more expensive Ultra shelves have multiple layers of foam and a stainless-steel top sheet that, like the shelf’s bottom sheet, is folded to increase rigidity. In addition, both the Standard and Ultra shelves feature a heatsink of damping foam that absorbs and converts mechanical energy to heat.

Symposium Osiris

The XTISO top shelf features the LDSS, which Bizlewicz states is especially effective in blocking low-frequency vertical waves, which are the most troublesome for sensitive source components such as turntables. This system uses damped, concentric, precision springs of stainless steel whose metal spiral decreases in diameter toward one end, like a pig’s tail. Although the shelf is optimized at the factory for the weight of the component it will support, changing components is typically not a problem; Symposium promises that the system works well within a fairly wide weight range.

Further, all of the rack’s shelves do double duty by providing two types of electronic-based signal protection. First, Bizlewicz claims, since the shelves’ exterior sheets are made of stainless steel, they form a Faraday cage, a type of electric shield that protects sensitive components from harmful EMI and RFI. Second, each shelf includes electrical component grounding comprising three stainless-steel screw terminals mounted on the shelf’s rear edge. Run a length of any good-quality wire (Bizlewicz recommends woven braid) from a component’s ground terminal or case to one of these screws, connect the shelves in series (i.e., in a daisy chain), and connect one of the bottom shelf’s screws to an earth ground or other grounding device.

Each of the Osiris Stealth Ultimate’s legs comprises a series of segments punctuated by Rollerblock modules and/or shelves, and is made of 99.99%-pure C10100 OFC, the purest copper commercially available. Commonly used in the manufacturing of semiconductors, superconductors, and particle accelerators, this type of copper has been electrolytically purified.

One might think that copper, a relatively soft metal that tarnishes or corrodes over time, would not be an ideal choice for an audio rack’s legs. Bizlewicz explained:

I have some OF copper legs here and while copper is softer than some other metals, if somebody hit me on the head with one, it would knock me out just as well! An OF copper leg is 2.5 times heavier than our aluminum leg (e.g., an eight-inch aluminum leg is three pounds and the OF copper version is 7.5 pounds!). So, you can see, the OF copper legs have impressive density, a bonus aspect of their exemplary mechanical grounding characteristics, and they are certainly strong enough to support thousands of pounds of weight without issue.

OF indicates that the copper is extremely pure, and thus has a faster mechanical transmission speed than a copper alloy. Copper is the second fastest metal in nature, second only to silver, and one place ahead of aluminum. Steel is further down the list, and wood further still. (The leg system of a rack is like a “lightning rod” that grounds spurious mechanical energy out of and away from the shelves, and their physical makeup is quite important.)

Over time, internal oxygen leaches from copper to its surface, causing it to tarnish. But OF copper does not tarnish as much. It’s possible to put a coating on the legs, which may help to preserve their finish (we hand polish the copper). We have some uncoated OF copper parts here that, after almost two years, still look beautiful, and haven’t darkened much.

The Osiris Stealth Ultimate’s footer assemblies, which must support all of the rack’s weight, each consist of a reversible tellurium-copper spike (one end pointed, one end flat) screwed into a 1.6-pound cone of OFC, also polished to a mirror finish. Tellurium copper is a harder form of copper with extremely high electrical and thermal conductivity and, you guessed it, a high speed of mechanical transmission. (The spikes of most other racks are made of less expensive, much “slower” steel or aluminum.)

The spikes rest in Symposium’s puck-shaped Precision SuperCouplers. Designed for use on wood floors, these are made of 7075 aluminum precision machined to make their top and bottom surfaces almost perfectly parallel. Their hard-coat black-anodized finish differs from the surface-coloration process used on some audio components and the oxidization process used to blacken the Osiris Stealth Ultimate’s shelves. According to Bizlewicz, it results in an exterior coat that’s harder than most steels, to produce a mechanical “skin effect” that improves both coupling and resonance neutrality.

Symposium Osiris

The bottom of each SuperCoupler is pierced by a matrix of holes that Bizlewicz says act as a waveguide to enhance mechanical surface coupling, and thus the transmission of mechanical energy to ground.

Like Symposium’s other racks, the Osiris Stealth Ultimate is customizable and modular. While it comes in various standard heights and internal shelf clearances, these can also be specified by the customer. The buyer can also specify the number and locations of the rack’s shelves and leg sections, to accommodate system changes.

The three-shelf review sample, custom-built to roughly the same height as my three-shelf Symposium Standard rack, measured about 28”H including the Precision SuperCouplers. The XTISO top shelf measured 25”W x 22”D, the two lower Ultra shelves 21”W x 21.5”D each.

Killer legs!

Although setting up a Symposium rack is surprisingly easy, Peter Bizlewicz came to my home to set up the Osiris Stealth Ultimate. We first positioned the SuperCouplers on my wood floor, then placed in them the footer assemblies, spikes down. From there we built upward, screwing into place a base plate, leg segments, Rollerblock modules, the lower Ultra shelves, and finally, the XTISO top shelf. The only tool we used was an Allen wrench (included but barely needed) and a level. In fact, setup was so easy that it made my memories of setting up other racks seem like bad dreams. (Now where did I put part C-17 . . . ?)

Fully assembled, the Osiris Stealth Ultimate was a gorgeous and elegant head turner. Its mirror-finish copper legs, set against its black shelves, looked nothing less than stunning, and every part of the rack seemed machined to perfection. Symposium may have an unpolished website, but their racks’ elegance, beauty, and quality of parts and workmanship take back seats to those of no competing products, regardless of cost.

I carefully loaded my Esoteric K-01X SACD/CD player and digital-to-analog converter onto the new rack’s XTISO top shelf, and my Stanford Research Perf 10 rubidium clock onto one of the lower Ultra shelves. As those components had previously sat on a three-shelf Osiris Standard rack with two Standard shelves and one Ultra shelf ($5395), they each received a shelf upgrade. As with my old rack, I left the third shelf empty.

According to Bizlewicz, once loaded, the Osiris Stealth Ultimate rack takes two to three weeks to settle in. This, he states, is due to the stabilization and bonding of materials, including adhesives, contained in the shelves and leg system.

Listening: “In the madness, you have to find calm.” -- Lupita Nyong’o

My Symposium Standard racks sonically trounced my old IKEA tables. I was thus skeptical that the new Osiris Stealth Ultimate, which contained only my digital front end, would do the same to the Standard. Boy, was I wrong.

In the recording by Daniel Barenboim and Radu Lupu of the Allegro vivace of Schubert’s Piano Sonata for 4 Hands in C Major, D.812 (“Grand Duo”), (CD, Teldec 0630-1746-2), the two pianists simultaneously strike dramatic dominant octaves. From these notes alone, it was obvious that the Osiris Stealth Ultimate had greatly improved my system’s sound. I played those octaves loudly and repeatedly. Each time, the leading edges were much cleaner and more precise than I was used to, and the sustains were longer, and more clearly segued into the next note. Further, the reverberations exhibited a previously obscured sense of calm.

The Osiris Stealth Ultimate went on to uncover the hidden, halcyon nature of virtually every recording I played. Particularly above 2.5kHz, Midori’s violin in the Allegro assai of Beethoven’s Violin Sonata No.8 in G Major, Op.30 No.3, from her Live at Carnegie Hall (16-bit/44kHz FLAC, Sony Classical), sounded much less congested and agitating.

In Duke Ellington’s iconic 1935 composition “In a Sentimental Mood,” performed by the Nick Brignola Quartet on Nu Force Live! BluePort Jazz Sampler (16/44.1 FLAC, BluePort BP J015), Brignola’s baritone saxophone now sounded more airy and soothing, and the round, sweet nature of his reed more apparent.

Perhaps the most striking example of this calm was demonstrated in “Marias Vaggsang” (Mary’s Lullaby), from Hush! The Angels Are Singing, with Karin Winter conducting the Taby Church Chamber Choir -- an unusually gorgeous recording made in a 13th-century church near Stockholm, Sweden, and remastered by the late Winston Ma (SACD/CD, Proprius/First Impression Music 049). In a display of true audiophile magic, the Taby Choir’s delicate voices were now rendered with ravishing stillness and grace.

But at the same time that the Osiris Stealth Ultimate brought a sense of serenity to my system, it also enhanced detail and transient response. Better microdynamics were evident in those opening octaves of Barenboim and Lupu’s Schubert performance, where it was now easier to hear that one of the keys was held down longer than the others. Similarly, in the Beethoven, it seemed that the interior resonances of Midori’s violin were more fully revealed.

Moreover, in “Eh via, buffone, non mi seccar!,” an extended passage of recitativo secco (voice accompanied only by harpsichord) in Act II of Mozart’s Don Giovanni, in the recording with Carlo Maria Giulini conducting the Philharmonia Orchestra and Chorus (CD, EMI Classics 56232), the subtle inflections of Eberhard Wächter (the Don) and Giuseppe Taddei (Leporello) were now more marked.

Symposium Osiris

With respect to transients, in the chorus O Fortuna, which begins and ends Carl Orff’s Carmina burana, the crash of the mallet on the big bass drum in the recording by Donald Runnicles and the Atlanta Symphony Orchestra and Chorus (SACD/CD, Telarc SACD-60575) had more powerful and visceral slam. In the Shubert four-hands sonata, the players’ keystrokes were more finely penetrating, with more weight and impact.

Also improved were soundstaging, imaging, and focus. From the first three emotionally charged notes of Gino D’Auri’s Fernandes guitar in “Guajira Antiguan,” from Flamenco Mystico, on Audiophile Reference I: Classical Music (CD, FIM 006), it was obvious that the entire soundstage improved. The notes now spanned a much wider soundfield, and were much more full-bodied and focused. And because the background was now more silent, the notes “spoke” more clearly.

In Hush! The Angels Are Singing, the church’s ambience was more audible -- the reverberations of the choir’s voices off the walls and ceiling were more evident. In the Don Giovanni recitative, Wächter’s and Taddei’s various positions on the stage were more pronounced. In short, everything I played with the Osiris Stealth Ultimate supporting my system was presented with a wider, deeper, slightly taller soundstage, and the images had more three-dimensionality and focus.

My system’s low-frequency performance also improved. Distortion at the bottom of the audioband can create a warm, fuzzy, pleasing illusion of fullness that a listener can grow used to but that is nonetheless false. The Osiris Stealth Ultimate reduced this distortion, restoring the accuracy and extension of the low end. Although some might at first think the low bass sounds leaner, all that’s happening is that it’s no longer bloated.

This bottom-end improvement was demonstrated in the overture of Mozart’s The Marriage of Figaro, with Jane Glover conducting the Royal Philharmonic (CD, Royal Philharmonics Masterworks 28040). At first blush, the thunderous tutti seemed a bit less fulsome with the Osiris Stealth Ultimate, but further listening revealed that the lower winds, particularly the horns and trombones, were now much more audible, where previously they’d been obscured by the lower strings, which had sounded unnaturally distended. While flutes, oboes, and clarinets were still a bit lost in the mix, that may very well be the nature of the recording.

Prior to the Osiris Stealth Ultimate’s arrival, I’d expected that it would improve the sound of my system more than my Standard Symposium had -- I just wasn’t prepared for the degree of improvement. But I’d also expected to hear changes in tonal balance and/or voicing due to the addition of the copper legs, and I didn’t. When I told Bizlewicz about this, he wasn’t surprised; he said that the legs are so damped that they don’t resonate enough to affect voicing.

It’s only rack’n’roll, but I like it

The Osiris Stealth Ultimate makes fools of audiophiles (like me) who continually upgrade components in search of better performance, never knowing what those components are capable of. Sonically and aesthetically, it takes a back seat to no competitor I have heard or seen, regardless of cost, and it definitively outperformed my lower-priced Symposium Standard racks. Were this rack sold by almost any other company, it would likely cost $25,000 or more. Indeed, its parts alone, if melted down, would fetch a very pretty OFC penny. A rare blend of value, good looks, and performance, it’s an easy recommendation.

. . . Howard Kneller

Associated Equipment

  • Power amplifier -- Esoteric A-03
  • Preamplifier -- Esoteric C-02X
  • Sources -- Esoteric K-01X SACD/CD player and DAC, Stanford Research PERF10 rubidium clock, Windows 10 computer running JPlay and JCAT USB card
  • Speakers -- YG Acoustics Kipod II Signature
  • Subwoofers -- JL Audio Fathom v2 (2) with CR-1 active subwoofer crossover
  • Interconnects -- Synergistic Research Atmosphere Level 4
  • Digital links -- Synergistic Research Galileo LE USB, JPlay JCAT USB
  • Speaker cables -- Synergistic Research Atmosphere Level 4
  • Power cords -- Synergistic Research Atmosphere Level 3
  • Power conditioners and distributors -- Synergistic Research PowerCell 12 UEF SE and QLS power strips
  • Isolation devices -- Symposium Osiris Standard racks, Synergistic Research Tranquility Bases, Custom Isolation Products amp stand, Silent Running Audio VR fp Isobase, Synergistic Research MIG 2.0s, Symposium Rollerblocks Series 2+ equipment supports
  • Room treatment and correction -- Synergistic Research Acoustic Art System and HFT and FEQ room-treatment devices
  • Misc. -- Synergistic Research Grounding Block and Black Discus Audio System Enhancer

Symposium Acoustics Osiris Stealth Ultimate Equipment Rack
Price: $12,500 USD
Warranty: Five years parts and labor.

Symposium Acoustics
49 Cannonball Road
Pompton Lakes, NJ 07442
Phone: (973) 616-4787
Fax: (973) 616-7848