Back Issue Article

July 2001

Blocks and Links: Symposium Rollerblocks and Walker Audio High Definition Links

I’ve recently become the unwitting beneficiary of direct personal exposure to two different isolation devices that are based on a similar concept but implemented differently. I've already explained the exact workings of the Vistek Aurios MIB devices in an earlier article. This month's first subject also isolates supported equipment from extraneous vibration while preventing it from "infecting" other components with self-generated parasitic resonances. Instead of using three ball bearings per device, as the MIBs do, the Symposium Rollerblocks use a single ball-in-a-cup approach. This recipe has the equipment rest directly atop the ball rather than the upper aluminum shell of the MIBs. The mirror-polished cup is carved out of a single block of hard-alloy aircraft aluminum. On the shelf-facing side, this block has been drilled out into a honeycomb pattern. Its holes are plugged with a yellow hard-foam material.

Three different grades of ball bearings are available: chromium steel (standard) and grade 25 or 3 tungsten carbide (both optional). As you upgrade from steel to carbide, the Rockwell hardness rating increases from 60 -- already harder than most steel -- to 90. This extreme hardness requires machining with diamonds. The 25 versus 3 grade indicates the precision of roundness in parts per million. A grade-3 rating is the most perfect measure of roundness achievable with current state-of-the-art manufacture. Not only is it very costly to produce, it must also be considered a sign of the extremes to which the Symposium folks feel compelled to take their designs.

A set of three standard Rollerblocks costs about the same as the equivalent Aurios trio -- $299 USD. Before I report on the Symposium sonics, a brief comparison between setup protocols. The Aurios, by virtue of their raceway's profile and width, allow for only minimal motion before they bind up. This requires perfect leveling of whatever surfaces on which they’re deployed. The Rollerblocks are much less fussy -- their spherical depression without rim and single ball allow plenty of movement to accommodate even slightly cockeyed shelves. For components with uneven bottoms or ventilation slots, Symposium includes thin self-adhesive steel plates that are inserted between the ball tops and the component.

Rollerblocks are easy to set up. Practically speaking, you can't use them under floorstanding loudspeakers -- not that you contemplated this usage until now. You can use the Aurios MIBs, though. As long as your speakers are weighty enough, turn the little dimples on their bottoms into spike protectors. This allows full flotation without sacrificing stability and yields remarkable returns. Atop short-pile carpet, a suitably sized and leveled granite tile will create a firm foundation for the bearings. However, truly lush carpet forbids attempts at suspending speakers for now, or any notion of safety and stability would be gone with the wind like tumbleweed.

Like the MIBs, the Rollerblocks create a walking-on-eggs effect for the gear they support. If heavy power cords, interconnects or speaker cables exert too much pull to upset the relative balance, a judicious repositioning of the bearings remedies the situation. Some additional dressing of the cables might also be necessary. Because the component's weight creates the actual coupling effect with the bearings, light gear definitely benefits from sandbags, lead bricks or other mass-loading devices to avoid going into orbital spin.

The sound of walking on eggs

My second "Earmarked!" column described the surprising effects of having your audio components do the dance on a buncha fancy balls. I described these effects as the appearance of space that loosens the sonic fabric's tight weave to stretch and expand it into all directions. Benefits are increases in clarity, resolution, air, intelligibility and bass definition.

Removing the MIBs and inserting the Rollerblocks into the system proved that both devices operate in the same domain of sonic-resolution enhancement. The Rollerblocks simply strike me as an even more effective version on the same theme. I experienced a heightened sense of transparency, a deeper and broader soundstage and even firmer control in the bass. To detail these bass improvements, envision the impact of a bombshell. If the actual impact is the attack of a very low but powerful bass note, the debris from the explosion is the "boom" that surrounds such notes in most real-world rooms. A well-damped system shortens the amount of time it takes for the dust to settle. A really dry environment reproduces the impact only and absorbs the "boom." The Rollerblocks duplicated the effect of such an over-damped environment. They subtracted the extraneous sonic debris from around individual bass notes to give my system (via the Triangle Ventis XS speakers) the tautest low-frequency response I've yet enjoyed.

Higher up in frequency response, the Rollerblocks created what seemed like sweetness in the upper midrange. In the context of this system, it made the previous setup seem slightly harder in that region. Think of the Symposium version more correctly as a subtraction of this subtle hardness, rather than the addition of a pleasing coloration. These devices also enhanced dynamic range, as though the outer limits between quiet and loud passages had been further stretched apart. In the treble, the added detail paid dividends in image precision and localization. Isolating components from each other and their support structures via the Rollerblocks decompresses the internal musical structure and releases more details, subtler inflections and finer gradations of tonal colors. Another way of describing these effect is an overt increase of resolution that removes spider webs, dust and crud from the sonic fabric. It won't take any glasses to notice, either. The effects are pronounced and accumulative.

Judging from the experience in my system, adding Rollerblocks from component to component simply intensifies the results. Whether that's universal (i.e., installed in various systems, could there be a limit as to how many components can be floated before you sonically take backwards steps?) I don't know. This is just another reminder that you need to try such tweaks first. Personally, I'm wholeheartedly endorsing Symposium's Rollerblocks and recommend that you evaluate a set in your own system at the earliest opportunity.

More treacherous tweakery -- the high-wire act

While we're at it, let's investigate another wacky audio toy that turns out to work as advertised -- the Walker Audio High Definition Links (HDLs or Links for short). I flashed on "high wire" because the HDLs use very skinny wire and work way up high in the frequency domain.

The Links are outboard Zobel networks. They're inserted in parallel with your loudspeaker cables. Positioned between your binding-post nut and the speaker cable such that the actual cable-to-speaker connection remains uninterrupted, the Links go across the hot and ground terminals. Two pairs of Links are required for biwiring. That’s how I used them on my Triangle Ventis XSes.

A Zobel network consists of a resistor and cap in series and acts as high-frequency filter. The HDL’s filter frequency is set to 1.5MHz. The parts doing clean-up duty are fully encased in a slim wooden body to resist damage from prying fingers -- and, presumably, copy cats. In Lloyd Walker’s own words, the resistor is a nude design of his own as is the capacitor. He claims ridiculously high parts quality that required customization -- nothing suitable was available from the usual vendor suspects. The leads and spades are solid silver, and this really helped when it came to bending the Links into place, especially when your speaker binding posts are stuck inside the flea-sized real estate of certain crammed plastic terminal cups.

Internal Zobel networks are occasionally employed on amplifier outputs to avoid high-frequency oscillation noise or other ultrasonic hash from exiting the circuit. Adding external Zobels like the HDLs into a signal chain with preceding internal Zobel networks will affect the operative filter frequency. Used with such amps, the Links' filtering action could conceivably occur much closer to the audible frequency spectrum. Such a rare case would preclude their recommended use. Why would anyone insert anything between his amp and loudspeakers except for speaker cables? To attenuate RFI noise that your speaker cables pick up like busy little antennas, and/or to remove high-frequency garbage that rides on the music signal and originates with the actual components (especially digital ones). Incidentally, Merlin speakers are outfitted with their own external Zobel networks.

Do the HDLs work? Like a charm. Do they screw up the signal? Are you kidding -- at 1.5MHz? However, this was a fair concern. Parts quality of such networks does become of paramount importance. If I told you that Lloyd Walker used to work on the wiring of nuclear-reactor cores (he knows a thing or two about hypercritical system junctures), our instinctively adverse reactions to such an idea should be more mellow.

In fact, think of the Links as electronic ball bearings -- in their own non-mechanical domain, they very much accomplish the same results as the Symposium Rollerblocks. Where the Rollerblocks attenuate or suppress mechanical intermodulation, the Walker Audio Links attenuate or remove high-frequency hash. Both are forms of noise. Removing them simply uncovers more of the signal. You gain potent enhancements in clarity, treble sweetness, transient speed and microdynamic scale. The most surprising improvement (as SoundStager Bill Cowen noticed in his system) may occur in terms of bass definition and enhanced delineation. Don’t assume that the HDL's point of attack in the ultrasonic region won't affect the entire audible spectrum -- it does. Why this is I'm not sure, but my ears clearly hear that everything from bass to treble is affected in the same benign fashion as the bearings. At $295 per pair, the HDLs even cost the same as the Rollerblocks.

After I played with the Links at length, I penned my observations for this column. I then e-mailed my golden-eared buddy BK, who's a firm believer in Walker's Valid Points. How did the HDLs work in his various retail systems? After all, they feature components very different from my own and might thus interface differently. His unedited reply is telling:

The links piss me off -- frigging piece of wood with some exotic parts I can't see, with some cheesy-looking silver wire and silver spades. But nothing makes my Sound Labs, my ProAcs, my Red Roses, my Meadowlarks or my Soliloquy 6.2s sing like those damned things. I can't live without them!

Voting with my wallet

I can now imagine the question that will be fired at me: "If you had $300 to spend, where would you begin?" Let's start with a disclaimer: I wouldn’t spend $300 on any accessory unless my total system expenditure was already on the far side of $6000. That said, I’d put a set of Rollerblocks under my source component or tube amp. Or I might go for the Links at the speakers first. It’s honestly hard to quantify the individual changes and determine a sequence of seniority. Each insertion or removal of an accessory creates logarithmic effects. Still, source and speakers seem to be the two most critical system parts that will benefit most drastically from dry-cleaning of noise pollution.

Also, the Rollerblocks and HDLs work extremely well in conjunction. They both fall into the broad category of audio accessories, or tweaks, but their results in a well-balanced system nearly warrants calling them components in their own right. Obviously, core components like CD players, preamps, amps, speakers or even cables are absolutely essential whereas tweaks aren't -- a system works just fine without them. But, once all core components are properly in place, secondary components like the HDLs and Rollerblocks can catapult a system's performance from simply working to phenomenal.


A phone call from Vistek has pointed to the necessity for another tweak column. Not a firm to stop product evolution past its first-generation model, Vistek had already introduced two additional bearings. The Aurios Pro Bearings and Aurios MIB 1.2 are both based on a new-and-improved raceway geometry. They merely differ in their respective weight-bearing capacities. Setup limitations based on perfect leveling requirements are supposedly transcended. Sonic improvements are likewise said to go quite beyond the original MIBs. Watch this space.

Symposium distributor Jamal Instrum of Foss Audio also sent me two Symposium Svelte shelves to use under my speakers. His audio care package further included nine grade-25 and three grade-3 tungsten carbide balls. This broad assortment of toys proved too overwhelming to tackle all at once. Before I attempt to discern sonic differences between increasing hardness and roundness tolerances in ball bearings, I opt for a brief respite from tweaking madness. Did I mention that Lloyd Walker threatened to send me a complete contingent of Walker Audio Valid Points, never mind temporarily rewiring my system with Omega Mikro cables?

So far, all of this crazy stuff truly works. None of it caused any "Am I imagining stuff?" head-scratching. Still, before I dip into these waters too deeply all at once and wreck havoc on your financial sanity and willingness to believe any of this, a final (and perhaps redundant) word of caution: Some tweaks are great; others, like the Rollerblocks and HDLs, even fabulous and addictive. But don't go overboard and put a $1500 power cord on a $225 DVD player, OK?

...Srajan Ebaen


Symposium Rollerblocks
Price: $299 USD (set of three).
Warranty: Five years parts and labor.

Symposium Acoustics
Wayne, NJ
Phone: (973) 616-4787
Fax: (973) 616-7848

E-mail: info@symposiumusa.com
Website: www.symposiumusa.com

Walker Audio High Definition Links
Price: $295 USD (set of two).
Warranty: Two years parts and labor.

Walker Audio
1139 Thrush Lane
Audubon, PA 19403
Phone: (610) 666-6087
Fax: (610) 666-5057

Website: www.walkeraudio.com  

Symposium responds:

Thank you for your well-written and informative review of the Rollerblocks.Your professionalism and attention to sonic detail echoes our commitment to the "holy grail" of audio, and we're grateful that there are reviewers like you out there who not only hear differences, but are unafraid to talk about them.

I would just like to respond by illustrating some of the reasons for the sonic benefits which you have noted in your listening tests, such as the "sweetness" in the upper midrange you heard when you substituted the Rollerblocks for the other devices which had been in use previously. I'd like to reiterate that this is not something which has been added to your system by the Rollerblocks -- but rather something which has been taken away: noise! Specifically, in the substitution you made, the culprit is bearing chatter. We have gone to great pains to make the "race" of the Rollerblock -- that is, its cup -- a precision, polished surface whose job it is to reduce bearing noise as much as possible as the ball oscillates on its surface. Any kind of surface irregularity here will be audible in the critical upper midrange/lower treble range, and will be discerned as "more" energy -- which is often mistaken for more information. While it is true in a mathematical sense that this is more information (as long as it is purely random), it is information which has little or nothing to do with the original signal -- or, in other words, it is extraneous distortion! Much like a tire that makes noise as it rolls over a road surface, a bearing in a race creates noise or "chatter" as it rolls. And, like tires, the fewer bearings you have, the less noise you can ultimately have, all other things being equal. The Rollerblocks use one ball and only one ball for this reason.

Also, I would like to mention the technology behind the Rollerblock's body. The Rollerblock body isn't just a stamped-out receptacle to hold the ball; rather, it is a carefully designed, machined (typical unit to unit tolerances are in the realm of about 50 millionths of an inch) and finished receptacle which enables efficient energy transmission between component and support surface. Like a good cone, the Rollerblock provides an all-important drainage path for energy to escape from the component to mechanical ground. The "matrix" of holes (seen in the picture as the yellow dots), filled with an absorptive acoustic foam, act as a crude waveguide and improve energy transmission without adding resonance. This part of the Rollerblock is responsible for much of the improvement in dynamics which you have noted. Early experiments with prototypes which did and did not have this matrix but were identical in all other respects clearly demonstrated the effectiveness of this feature (and by the way, it is patented).

In summary, I again would like to extend to SoundStage! my thanks for its excellent forum on things sonic, and to Srajan my personal thanks for an incisive and honest appraisal.  We are grateful for your clearly presented and well-thought-out review, and I look forward to your "next installment" in which you get into some of the upgrades to the Rollerblock system, namely the grade-25 and grade-3 tungsten-carbide balls.

Symposium's mission is to stretch the envelope of performance in order to advance the state of the art; thanks for letting us know that we've still got "the right stuff."

Best regards,

Peter Bizlewicz
Symposium Acoustics


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