Before I report on audible performance, let's cover a certain technological background which may appear similar to other existing devices and thus could cause confusion or at least uninspected assumptions. The most obvious one is the lack of shelves. While the use of panels is absolutely essential for loudspeakers and arguably also for at least affordable component enclosures, it is anything but essential for the storage or placement of components. Once you buy into the notion that shelves are functionally essential, it naturally follows that you must now minimize their inherent resonance (or ringing if you use glass or stone) via complicated and expensive material/constructional applications. But why even descend into this mess if shelves are clearly unnecessary? Besides EquaRack, the Spider by Finite Elemente and Rack of Silence designs eschew shelves altogether for this very reason.

In the absence of shelves, something naturally must substitute as points of support. Enter the elastomeric interfaces of the Spider Rack or the bearing interfaces of the Rack of Silence and EquaRack's Vector/BearingMounts. In the latter case and as supplied for this review, these BearingMounts use expensive, true top-and-bottom precision ball bearings. Because of the multitude of audio isolation devices that employ balls, it's imperative to remember that bearing balls per se do not equate to ball bearings. Put differently, just because something uses a ball does not make it into a ball bearing. A captured ball such as employed in the Grand Prix Audio Apex, Stillpoints footer, Vibrapod Cone or Ceraball is a bearing ball but not a rolling-member ball bearing.

A true ball bearing for audio use employs a ball which travels (rolls) laterally inside either a spherical or conical race. This combines isolation and damping. Damping occurs because in order to move at all, the ball must travel upwards inside the depressed race, lifting the weight of the component which bears down on it and thus naturally attempts to prevent said upwards motion. These opposing forces dissipate or use up the input vibratory energy as work. The visible response motion of the bearing to input vibrational signal will likely be so infinitesimal as to remain entirely invisible. Fixed-ball designs do afford isolation but not this counter-motion damping action. While the EquaRack BearingMounts may thus look similar to certain other devices using balls, they're not. However, Symposium's RollerBlocks and the Japanese Darumas are true ball bearings as well (though the RollerBlocks are only half bearings i.e. lack the upper race which now has the ball in direct contact with the component bottom.) What distinguishes the bearing in EquaRack's BearingMounts from those two bearings as far as I can discern? Higher-performance materials and finishes, the implementation of additional visco-elastic damping and further features explained in detail on the manufacturer's website.

The CLD (constrained-layer design) sheet of visco-elastic polymer inside their bases adds a shock rebound value far higher than a soft elastomeric material with lower durometers or hardness values would. As far as I know, this combination of a true ball bearing with visco-elastic damping is unique to the EquaRack BearingMounts. Next, their superior execution has a name: Tungsten Carbide. It appears in both the grade-5 ball and the races to create a true minimum-point load interface that won't deform under pressure.
Why is resistance to deformation so important? Picture a tool that engraves your name into the metal barrel of a pistol. It works with a small amount of hand-held pressure by applying electronically-fed high-frequency vibrations to its engraving tip. The vibrational input which audio components transmit into ball bearings -- plus their accompanying downward pressure -- turns such decoupling or isolation devices into quasi engraving tools. In fact, that's exactly what happens with inferior bearings. The applied weight deforms the ball into an ellipsoid as well as 'engraves' the receiving race with a dimple. This undermines both the minimum-contact principle of isolation and the inbuilt counter-motion damping potential. Sensitivity or the ability to respond to extremely minuscule vibrational input 'signal' is drastically lowered. Such sensitivity or effectiveness requires micro-point contact and perfect geometry and cleanliness of the race.

Naturally, the smaller the contact point, the higher the applied pressure or deformation values. Even a 14lbs DVD player will exert enormous weight once it is focused on three points the size of a needle tip. To resist deformation and degradation under such conditions requires extreme hardness for both the transmitting ball and the nesting races. While 'just' another bearing in principle, the EquaBearing BearingMount, upon closer inspections, reveals itself to be anything but. Incidentally, the circumvential O-ring bumper/girdle prevents excessive lateral displacement to avoid the endless hammock-like swaying of lesser bearings that offer isolation but minimal self-damping.

This exploration explains why these BearingMounts sport the rather exorbitant price tag of $300/ea. One must really think of them as having twin bearings since you purchase two races rather than one as with, for example, the well-known Symposium RollerBlocks. It turns out that EquaRack's designer Joe Ciulla has extensive experience in welding, fabrication and metal finishing and enjoys in-depth familiarity with industrial processes and their associated material sciences. This translates into EquaRack's use of a proprietary Tungsten Carbide formula optimized for dry bearing applications. It also explains the rack's 12-gauge steel channel TIG-welded end fittings and high-torque 50ft/lb connections. The terms industrial strength and EquaRack thus doesn't make a fancy but irrelevant connection of reporter hyperbole but is a simple fact.

Before we finally get to the audible impressions, two last pieces of installation advice: If you use the Spike Adaptors to penetrate carpeting with BearingMounts to 'float' the entire rack on BearingMounts, you must insert the spikes from above and gently raise the entire rack via the enclosed hex key after you've moved the rack into the final desired position. This ensures that the bearings are properly aligned before getting spiked, i.e. they don't become torqued under lateral displacement by not being perfectly dead-center underneath the central axis of the uprights. And for components of unusual unwieldiness or severely lop-sided weight displacement, one may need or want to use four Bearing or VectorMounts for support rather than the usual three. This could also be a final tuning option for components that don't require four support points but sound better that way.
Manufacturer's website