The Solid Tech Rack of Silence, Disc of Silence and Feet of Silence Isolation Devices

Some things just look too cool to ignore. So it was in Las Vegas at the 2003 Consumer Electronics Show, when I saw Solid Tech’s “Rack of Silence” in the Zanden Audio/Ascendo speaker room. I shot right to the “I have got to have that!” place in my psyche. And once that’s activated, a chain of events of which I am quite powerless over, is set into motion, always resulting in a much lighter checking account balance. 

The timing of this discovery couldn’t have been better. I needed a new home for my components and have spent the better part of a year checking out the offerings of many worthy manufacturers. As my system is centrally located out in the vast open space of my loft, I wanted something with visual impact and a bit out of the ordinary. My search left me rather surprised at how few designers of audio furniture take even the slightest aesthetic risk, how little emphasis they place on setting themselves apart from the throngs of rather ho-hum designs. After repeated unsuccessful attempts to locate the stands manufacturer at the show, I put my checkbook away and waited ’til after the show to get the ball rolling.

Back in New York, I got a hold of the designer, Mr. Bjorn Ohlson, founder of Solid Tech, and arranged for the delivery of the Rack of Silence Amplifier stand. Upon reflection, I was a little wary of the sonic effect the full stand would have on my acutely balanced system. As a result, I decided to start with the amplifier stand and take it from there. Built to the dimensions of my Jeff Rowland Model 302 amplifier, the amplifier stand arrived and was immediately put to the test. Keeping in mind that the Rowland Model 302 was designed with anti-resonance as a priority, I was shocked at the over all sonic improvement that the Rack of Silence imparted. With my apprehension quelled, I immediately called Bjorn and arranged to review the full Rack of Silence for my components. 

The Rack of Silence arrived partially assembled and within an hour, full assembly was complete. The fit and finish of the Rack of Silence is first rate. The combination of cherry stained beech wood shelving struts (black is an option) and the extruded aluminum pillars are gorgeous. While the stand appears massive, it is relatively lightweight though extremely rigid—a natural characteristic of the extruded aluminum pillars. While some manufacturers swear by mass as the cure for resonance control, the Rack of Silence uses spring suspension for the X-brace that acts as a shelf. At least two of the X-brace shelves must be fixed to the pillars at a distance of at least half the length of the pillars in order to provide rigidity to the structure of the stand, allowing the remaining shelves to remain sprung. Large-diameter ball bearings, used as an additional level of resonance control, sit in a groove carved out of the top of the X-shelf struts. The stand itself sits on the spring-suspended “ Discs of Silence.” 

There are two additional levels of support available to bolster the Rack of Silence: the “ Feet of Silence” and the above-mentioned “Discs of Silence”. The Disc of Silence is round with an open center. Springs that attach around the perimeter of the disc hold a rod with a flat cork-covered plastic cap in place at the center, creating a kind of trampoline. 

The Feet of Silence are more complex. A high gloss polished or blackanodized aluminum housing holds a floating bearing held in place by a sub-chassis that in turn is suspended by small gauge and UV resistant rubber bands. As the weight of the component falls on the bearing, it compresses the suspended sub-chassis held by the rubber bands. Each of these devices worked as advertised and contributed to the fine sound that the Rack of Silence made possible. Finally, each X brace shelf can be fixed to the pillars or suspended by springs as an additional form of isolation. In my stand, the top and bottom shelf are fixed, while the two middle braces remain suspended.

Bjorn Ohlson explains the Rack of Silence concept: 

“Since the most degrading vibrations/resonances are those with low frequency and high amplitude, our aim has been that the load carrying structure should have a natural high resonance frequency and in a corresponding way, low amplitude at resonance(less energy storage and a quick decay). Since it is the form, size and stiffness of the structure that determines its natural resonance frequency, we have chosen to avoid the large physical structures of shelf planes, and replaced them with struts that have a favorable stiffness-to-weight ratio for their size. The resonance frequency of the carrying structure has thus been shifted considerably higher up, resulting in lowered amplitude.

However, no matter what materials or concepts that the rack consists of, it is our firm belief that in order to obtain optimal performance, one must include effective isolation in the set up of an audio system. Any technique that does not provide isolation of external vibrations will only vary the amount of resonant stimulation added to the components concerned. It cannot reduce the level of baseline vibrations in the floor.

In order to achieve an effective isolation and uncolored reproduction, there must be a freedom of movement in all planes, and the resonance frequency of the isolation material must be outside of the 20-20,000Hz audio spectrum. Our different isolation systems like the Feet and Disc of Silence as well as the shelf suspension system have at normal load a resonance frequency well below 3 Hz. This means that isolation starts at approximately 4Hz, which is clearly outside the influence of the audio range. It should be mentioned that 100% effective isolation does not exist. For that reason, our system permits and facilitates isolation in up to three steps. Namely, with permanently mounted Discs of Silence at the floor end of the corner pillars, shelf suspension and/or Disc & Feet of Silence for the isolation as close as possible to the apparatus.”

Listening

With all my components arranged on the stand, the first thing I noticed was that everything bounced and jiggled around when the stand was nudged! This can be a bit unsettling when, for your whole life as an audiophile, you have dealt with spiked components and massive stands. My concerns melted away like a June snow when I pushed “play” and the digits were converted to sound. In broad terms, the Rack of Silence was able to bring the whole of the performance forward in space without any sharpening or brightening of the upper frequencies. There appeared to be more meat on the bones, as information came through in a more coherent and organized fashion. All of the smearing of detail that went un-noticed before became apparent when contrasted with the new presentation. What had been natural sounding system to begin with, improved in ease and refinement, allowing for higher listening levels without the penalty of harshness or hyper-delineation. With acoustic signatures of all pedigrees, be they conjured up in a studio or the real space of a concert hall, the Rack of Silence carved an additional layer of brick out from behind my speakers creating a broader, deeper canvas on which to render whatever was on the recording. Margo Timmons’ aching melancholy on track 1, Something More from the Cowboy Junkies’ “Lay It Down” (GEFD24952) occupied my room with a greater degree of presence than ever before. 

The Rack of Silence had an immediately recognizable effect on the dynamics of my system. Using Satriani’s “Devil’s Slide” off Engines of Creation (EK67860) as an example, The Rack of Silence added a degree of dynamic slam that kicked down the doors with S.W.A.T.-like aggression and absolutely ransacked my loft. My system sounded freer and less constrained. Micro dynamics were improved as well, becoming lighter and less encumbered. Tommy Flannigan’s playing on Sea Changes (ECD2219) sounded more fluid, graceful and nuanced. Josh Groban’s vocals on You’re Still You from his self-titled debut recording (WMG 48154-2) were rendered with an additional layer of detail, focus and dynamic nuance. This admittedly fluffy material is made palatable by the knowledge that Mr. Groban possesses an extremely powerful voice that holds great promise.

Conclusion

My experiences with isolation devices such as they stands, shelves or spikes has never led to a fulfilling long term relationship. While initially impressing, most of these devices proved to create some kind of shift in tonal balance, usually toward brightness or a “leaning out” of harmonic textures. As a result, I always ended up having to turn the volume level down, robbing me of one of my few last vices. On the other hand, combining squishy materials such as sorbathane would dull the presentation and put me to sleep in the process. The Rack of Silence, Disc of Silence and Feet of Silence creates that perfect blend of a lively dynamic range, and textural ease and coherency, yielding a complete sonic image that is just plain addictive. If you can put aside the years of conditioning your belief system that mass is the only way to go, then the Rack of Silence will reward you with its many sonic benefits and set you apart from the run of the mill, ho-hum designs your audio buddies have settled for.

Post script: At the end of the review process, I was able to try the amplifier stand on the Gryphon Encore amplifier. The results were much like that of the Rowland 302: greater ease, deeper soundstage, increased focus and dynamics. In other words, an across-the-board improvement, with zero trade-off. This repeatable result is a testament to the solid theory backing up a great looking product. 

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