select_150w_tThe realization that resonances can affect the sonic performance of audio equipment is an audiophile rite of passage. After not too long in the hobby, it’s inevitable that we confront and accept the not-so-obvious notion that the things we place under and even on top of our components can alter the sounds of those components. That’s the easy part.

201007_sra_400w_transDetermining how to control resonances so as to not only change but improve what we hear is a bit more challenging. Yes, you can try to understand the often-conflicting technical claims made by manufacturers of isolation devices. However, the conversation can quickly get very complex, particularly if you lack an advanced degree in engineering. 

Just look at the materials isolation devices are made of. Some manufacturers claim that resonances are best tamed by such common woods as oak, birch, or Canadian maple. Others assert that only a certain exotic wood will do; e.g., myrtle, teak, jabota, African blackwood, zebrano. Still other companies insist that you shouldn’t use wood at all; that the only ways to go are carbon fiber, acrylic, Sorbothane, or various stones, ceramics, or metals. Indeed, it might not be a stretch to think that, when Thomas Dolby wrote the song “She Blinded Me with Science,” he was buying from some lovely lady an isolation platform for his high-end audio system.

In light of the foregoing, my guess would be that many audiophiles take a scattershot approach to isolation, as I have. Over the years, I’ve accumulated a mélange of stands, platforms, cones, pucks, feet, mass-loading devices, cable risers, and the like. I’ve also spent countless hours tweaking these devices to get the sound just so. I was therefore reluctant to review Silent Running Audio’s new, custom-designed VR fp isoBASE platform. Setting up its feet, particularly for components that tend to be lifted off the rack by unwieldy power cords, can be a major pain in the keister. 

On the plus side, I was already familiar with SRA and some of their products, from a visit I made last year to the company’s sound laboratory in Hauppauge, New York, on Long Island. As I wrote in an article for SoundStage! that detailed that visit, SRA’s roots are in the design and manufacture of vibration and acoustical solutions for the electronics, military, and medical industries. Among many other things, SRA designs and makes isolation systems for nuclear submarines and advanced fighter jets. It even makes systems for the early detection of earthquakes. 

Also, SRA uses what they call Component Specific Design: each unit is custom-built to support a specific audio component. As company owner Kevin Tellekamp notes, the suspension system of a 2000-pound sports car is very different from that of an 8000-pound SUV. Similarly, he says, you wouldn’t want to use the same isolation platform for both a 26-pound CD player and a 150-pound amp. 

Thus, in light of SRA’s impressive street cred and its custom approach to its craft, I began to dismantle my isolation gear. 

Features: I can smell the chemicals 

SRA makes several lines of isoBASE isolation platforms, and just below their top-of-the-line Ohio-Class reference series is the new VR fp line ($300 to $785, depending on size and complexity). 

As with all SRA isoBASEs, the custom design of the VR fp models takes into consideration a variety of factors, including component type (e.g., amplifier, preamp, or source), weight, weight distribution, construction materials, and even the type of environment that the component will operate in (e.g., on the floor or on a stand). As explained below, rather than rely on a design based on any of the aforementioned hard materials, the VR fp units utilize a unique chemical-based solution. 

The exterior or skin of a VR fp isoBASE is coated with a catalyzed blend of rubber and cyclonically exploded glass, which is used to help limit static electricity, electromagnetic interference (EMI), and radio frequency interference (RFI). Under this coating is a proprietary, high-pressure hybrid laminate that’s 0.75” thick on top and up to 1.25” thick on its sides. 

Under each VR fp isoBASE are four spiked feet, each of which is attached to a module inside the unit. These modules provide the unit with six degrees of free motion: forward, backward, left, right, up, down. Incredibly, each module contains 80 internal parts. 

At the center of each module is a proprietary copolymer compound. According to Tellekamp, resonances travel from a component into a module, where friction occurs, producing heat within the compound. This modifies the compound’s darometer (hardness) in a rapid and predictable manner. Thus, he says, once a component’s tendency to create resonances is identified, each module can be customized to alter its darometer in such a way that all four modules, working together, quickly dissipate those resonances. I found this pretty interesting. Although a number of products are claimed to convert resonances into sonically harmless low-level heat, SRA is the only company I know of that uses the heat to change the physical state of the materials the platform is made of. 

The entire assembly process for the VR fp units is performed in a nitrogen tent so that impurities in the air do not make their way into the modules. Of course, there’s another reason you might not want air inside your isolation platform: Air is an efficient transmitter of vibration. In fact, at 70 degrees F and 50% relative humidity, air carries music from your speakers to your ears at 1128 feet per second. 

Each VR fp isoBASE is from 2” to just under 4” tall, depending on the characteristics of the component it’s designed for. IsoBASEs made for use on a rack are shipped with ultra-low-profile feet that are kind of neat; they make the component look as if it’s floating on the rack. The feet give the isoBASE enough space to dissipate the heat created as a result of the aforementioned chemical reaction. Floor-based VR fp units are fitted with slightly taller feet. In addition to dissipating heat, the taller feet give more clearance, so as to avoid any carpets or cables that could interfere with the unit’s powers of suspension. 

These aren’t your typical component feet. They’re injected with a polymer that Tellekamp has found absorbs resonances that enter the isoBASE from the underlying floor or rack. Moreover, Tellekamp recognizes that floor-based units are typically subjected to more ground-based resonances than are those placed on isolation racks. Accordingly, the feet for the floor-based units are often injected with three different polymers, depending on the component supported. According to Tellekamp, each polymer isolates a different part of the frequency spectrum: lows, mids, highs. 

Prior to being shipped, each unit is placed in an anechoic chamber and tested with a variety of tools, including accelerometer and oscilloscope. Tellekamp states that every VR fp isoBASE will isolate resonances down to 3Hz. 

Since the VR series has been around a while, and was reviewed by SoundStage! a number of years ago, I asked Tellekamp what’s new in the VR fp units. I was told that the fp modules are substantially simpler than before, which allows them to be easily modified to accommodate the use of a different component, should the need arise. The “fp” stands for “future-proof,” and each fp unit comes with this guarantee: First, SRA will forever reconfigure any fp isoBASE at no cost to the customer, should the component it supports be upgraded or replaced. The new component must entirely fit on the fp unit, with no overhang on any side. Second, in the event that the new component does not entirely fit on the unit, SRA will offer a trade-in allowance of up to 50% toward a new one. 

According to Tellekamp, this “future-proof” guarantee lets the audiophile enjoy the benefits of component-specific isolation while knowing that, should the desire to upgrade or change components later strike, that audiophile is covered. 

Setup: all my tubes and wires 

Tellekamp suggested that the best places to begin would be my amplifier and source component. After spending some time gathering all the required specifications for my Bryston 6B-SST2 amplifier and Marantz UD9004 BD/SACD/DVD/CD player, the latter modified by Tube Research Lab, Tellekamp showed up at my door with the isoBASEs. The costs of the units came to $350 (disc player) and $450 (amplifier), and each came in its own custom-shaped wooden crate. 

He recommended that we set up the isoBASE for the amp only, and leave the one for my Marantz disc player in another room, to install another day. Indeed, he warned me to leave it there for several weeks. He wanted me to observe any changes in performance one isoBASE at a time. 

Tellekamp prefers starting with the amplifier and then moving back toward the source component -- much to my surprise, he believes that the amp is where the biggest bang for the buck is, because amps often contain such things as large capacitors, beefy power supplies, and tubes, all of which create resonances. Also, amps are often placed on the floor close to speakers, which subjects them to even more vibration. These factors reportedly place an amplifier at much higher risk of sound-degrading vibrations than, say, even a disc transport. 

Because each isoBASE is made to precisely the length and width of the component that will rest upon it, the visual result of placing my Bryston amp on its isoBASE was striking in its good looks. 

Performance: sweet as any harmony 

Installing the first isoBASE brought sonic benefits that were not subtle. Nonetheless, these improvements were not what I had expected. While the entire audioband benefited a bit, the most significant changes were found in the lower frequencies. For example, in “Too Rich for My Blood,” from Patricia Barber’s audiophile standard Café Blue (CD, Premonition PREM-737-2), Michael Arnopol’s double bass was much more defined. On “Nardis,” Mark Walker’s drum solo went deeper than I’d ever heard before. 

The only problem now was that every time I went into the other room, the crate containing the other isoBASE stared me in the face. I tried to stay away from it, but it kept attracting me. This continued for about a day. Finally, I could take it no more. Abandoning any pretense of moral fiber or self-control, I pried it open and placed the second isoBASE under my Marantz UD9004. 

At the time, I was listening to The London Philharmonic Orchestra Plays the Music of Pink Floyd (CD, Point Music 446 623-2), at best a mediocre-sounding disc. Even so, it was clear that everything had now snapped in place. Leading edges became more pointed. The decays of the bells and cymbals in “Time” and “Brain Damage” were longer. Previously hidden spatial cues emerged that positioned the performers more precisely on the soundstage. In improving the bass, the first isoBASE seemed to have laid the foundation for the improvements that the second base now brought to the soundstage, as well as to the middle and upper registers. 

The improved leading edge especially benefited Depeche Mode’s Violator (CD, Sire 26081-2). Like many tracks on this album, “World in My Eyes” uses short synthesized sounds that have sharp transient attack. With the two isoBASEs under my amp and player, these attacks became more delineated, and the track now had more of the terse punch that I imagine the band had intended. Not surprisingly, as the sounds on this track became more structured, the integrity of the space between the sounds improved. And no matter what disc I played with the isoBASEs in the system, the noise floor dropped. There was no sonic downside. 

Even so, I’m not foolish enough to think that the VR fp isoBASEs represent the last word in vibration control. For example, there’s SRA’s own Ohio-Class reference platforms, which have been reviewed by SoundStage! and won our Reviewers’ Choice award. Even so, I can’t help thinking that the isoBASEs are screaming bargains. 

Comparison: deep as any ocean 

The hodgepodge of isolation devices I’ve accumulated over the years includes products from Bright Star Audio (including several of their $750 IsoRock Reference platforms and a heavy mass-loading plate), cones and jumbo pucks from Black Diamond Racing, Heavy Hat weights from Mapleshade Records, some nondescript sand-filled platforms, and, last but not least, my own DIY wooden amp stands. If insufficient to fill an ocean, these products would certainly fill a large bathtub or two, and their collective cost exceeds by several times that of the two isoBASEs. 

The isoBASEs sounded much better than the above-mentioned assemblage. I keyed up Live! BluePort Jazz Samples, a well-recorded collaborative effort of NuForce Media and BluePort Jazz (DVD-A/CD, BluePort BP J015). Track 1 on both discs is “Evan Evans,” named for the son of the great American jazz pianist Bill Evans. Pianist Mike Garson brought in for this recording what is probably one of the greatest pianos ever made -- a $180,000 Fazioli. With both the DVD-A and CD versions, the isoBASEs let the strikingly delicate and crystalline sound of each of the Fazioli’s notes come through with greater clarity than I had ever before heard from my system. 

This result is no knock against the other products -- after all, I mixed together somewhat haphazardly devices made by different manufacturers, in a testing methodology that tells me precisely nothing about anything. Yet even when I attempted a somewhat fairer comparison, pitting the isoBASEs against the Bright Star Reference units, I was stymied. Unbeknownst to me until I’d moved the Bright Stars off their dusty amp stands was that the soft, Sorbothane-like feet that decoupled them from the stand had, over time, been squashed flat as pancakes by the components resting on them. I have to think that this didn’t do much for their resonance-absorbing properties. 

Out of curiosity, I asked Kevin Tellekamp how well the chemical compound in the isoBASEs would withstand the tests of time. He told me that he’s used computer modeling to perform virtual usage tests that assumed extreme swings of temperature over a period of 200 years. According to him, these tests revealed changes in the composition of the copolymer that were so small that measuring them was “pointless.” 

Suffice it to say that a follow-up review, with new feet for the Bright Stars, would be appropriate at some later time. Until then, if your isolation platforms have soft feet and have been around for a while, you’d best check them; replacements may be in order. 


Unlike Thomas Dolby, Silent Running Audio is no one-hit wonder, and rather than blinding me, the VR fp isoBASEs brought to my system increased transparency, resolution, and focus. Indeed, it doesn’t take a rocket scientist to figure out that these products are fairly priced. Had you told me that someone had designed a custom-based isolation platform for one of my components and was willing to ship it to me in a beefy, custom-made wooden crate for as little as $300, I’d have said you were crazy as a soup sandwich. 

Even so, the one reason I might not purchase a custom isolation product is that, as a reviewer, I go through components fairly quickly. However, with SRA’s “future-proof” guarantee, that’s no longer an issue -- the fp units are reconfigurable to accommodate different components at little or no cost. Therefore, I give them a Select Component award for tremendous value and performance. For now, however, I’m going to forget about chemicals, jabota wood, and Sorbothane, and listen to some tunes. 

. . . Howard Kneller 

Associated Equipment

  • Speakers -- MartinLogan Summit X
  • Amplifier -- Bryston 6B-SST2
  • Preamplifier -- NuForce P-9
  • Source -- Marantz UD9004 universal player, modified by Tube Research Labs
  • Interconnects -- Synergistic Research Tesla Apex and Precision Reference, Synergistic Research Galileo MPCs on all signal cables and power cords
  • Speaker cables -- Synergistic Research Tesla Apex
  • Power cords -- Synergistic Research Tesla Hologram A (amplifier) and D (source), Precision AC (speakers) and T2 (preamplifier)
  • Power conditioners and distribution -- Synergistic Research Powercell, Synergistic Research QLS 6 and 9, PS Audio Noise Harvesters, DIY parallel filter

Silent Running Audio VR fp isoBASE Equipment Platforms
Prices: $300 to $785 USD, depending on size and complexity.
Warranty: Lifetime.

Silent Running Audio
325 Hubbs Avenue
Hauppauge, NY 11788
Phone: (631) 342-0556