Silent Running Audio • Scuttle Equipment Rack

SRA's less expensive equipment rack excels at presenting more of the music.

by Tim Aucremann | October 24, 2011

ou don’t need to understand string theory to know that everything vibrates. Compression waves in the air vibrate eardrums causing tiny hairs in the inner ear to wiggle at specific frequencies, generating electrical signals into the brain where they turn into the perception of sound. When those vibrations organize in a felicitous way, we may hear music. If the music comes from our stereos, those same compression waves cause vibrations in the audio equipment producing them.

Music is good for your ears but bad for the gear that reproduces it. Musically induced vibration physically alters audio equipment. A vibrating printed circuit board flexes all its components to a degree. The result is audible signal distortion. For example, consider what happens if the music you’re playing matches the resonance frequency of a capacitor -- say, a nice V-Cap CuTF like the ones in my Atma-Sphere preamp. The physical oscillation of the Teflon causes small variances in the spatial relation of the capacitor’s copper plate that yield tiny yet measurable differences in its capacitance. A few microns of displacement can result in a small voltage deviation. Compound that effect across all the caps in your system and then amplify it and you have chaos.

Airborne energy does the majority of harm to signal accuracy, but it is not the sole source of problems. Structural elements in your home absorb and transmit energy to each other and anything in contact with them. Wood floors resonate and flex; massive, rigid concrete makes an excellent vibration transmitter. Not only is your system bombarded by air- and floor-borne energy, your components generate and propagate vibration as a byproduct of their own operation: power-supply transformers hum, digital transports whir, turntables turn. All of it contributes to that veil of distortion hanging between the listener and the music.

Some audiophiles still consider vibration control as an add-on or an accessory. In the economy of audiophile dollars, vibration control tends to be underrated or tackled piecemeal. The phenomenology of distortion perception may give a clue why. We cannot appreciate the pernicious effect that vibration has on our systems until it is gone. Despite experiencing it, if we don’t recognize vibration’s effect, we may not take it seriously enough to pay for a solution.

Silent Running Audio (SRA) takes vibration control very seriously, and the staff thinks they have an affordable entrée in the war against distortion. It’s an equipment rack they call the Scuttle.

A new hope

or the past 18 years, Silent Running Audio has fought the battle to squelch bad vibes in audio systems. It's a company run by a music-loving physics and math prodigy with a collection of 25,000 LPs. There are sister companies specializing in industrial, medical and military applications, all espousing fanatical attention to detail and measurably effective performance. Review and end-user comments reveal gobs of accolades. Nobody, it appears, doesn’t like SRA.

The company grounds its products on real-world scientific research, data collection, modeling and testing, and then delivers solutions using innovative materials science and high-precision engineering. With its titanium endoskeleton, aged, air-dried hardwood, and CNC-quality joinery, SRA’s flagship Craz² audio rack is a bespoke vibration-isolation system with the look and feel of fine furniture and a reference-component price to match.

Now, along comes a new rack with a name derived from the nautical notion of breaking up or breaking apart a decommissioned or outdated vessel. The Scuttle aims to break apart vibration and energy anomalies. To build the Scuttle, SRA drew upon the same core competencies the company used to build the Craz², but there was an important difference: price. I don’t usually write much about product cost, but when a premier high-end manufacturer targets a new product in terms of affordability, heads will turn. Mine certainly did.

In the words of Kevin Tellekamp, the CEO of SRA, "The Scuttle design was actually in my head for five or six years before I started playing around with it in our modeling system. One day after yet another phone call from another audiophile searching for a high-performance, yet affordable equipment rack, I decided it was time to make my vision a reality. The goal for the Scuttle was a simple one, performance like Craz², but much less expensive." How sweet is that?

Kevin said it is possible to build a Scuttle to any size and configuration a customer wants -- custom builds are an SRA specialty. However, 99% of all Scuttles ship in two sizes: 30"W x 36"H x 22"D (three tiers supporting three audio components) or 47 1/2"W x 36"H x 22"D (three tiers supporting six components; this is what I received for review). A four-tier version for eight components is available, and SRA has made a few wide two-tier units, so there is some flexibility. Prices for these standard Scuttles range between $6600 to $8600, depending on tiers and width. By comparison, the smallest two-shelf Craz² starts around $11,500, and the prices go up from there.

So here’s the Scuttle brandishing SRA quality at roughly half the price of one of the premier audio racks on the planet. How can the company do this? Integral to SRA’s development process is an extensive set of testing tools and a resultant database of audio-component and parts measurements. SRA also designs, builds, and supplies isolation products for a host of high-end companies. Before making any recommendation, they test those customer’s electronics with their solutions. They capture size, weight, resonance frequencies, transmission curves, propagation responses and a slew of other material and vibrational characteristics. Sophisticated instruments and algorithms reveal that each piece of audio gear has its own unique vibrational fingerprint. When a manufacturer changes a component’s dimensions, a fabricated faceplate uses a new alloy or a company adopts different footer material, the fingerprint changes. To SRA, it is all measurable, and years of building custom isolation products mean a lot of accumulated data.

All this data serves as input to SRA’s Component Specific Design (CSD), the proprietary modeling process lying at the heart of Silent Running Audio’s technique for creating advanced isoBASE platforms and Craz² racks. When building isolation products for the exact equipment they will support, CSD gives SRA the advantage of knowing what problems they need to solve before construction begins.

With their wood frames, gray stone-like shelves and similar size, both Craz² and Scuttle are easy on the eyes. Beyond that, the Scuttle appeared to my untrained eye as an obvious departure from the Craz². Like a good parent, Kevin demurred, suggesting that the two racks are more alike than one would think based solely on visuals.

Where the Craz² is all about customization, SRA does not build Scuttles to individual component requirements. That’s one piece in the Scuttle's affordability puzzle. Nonetheless, Craz² and Scuttle share a lineage of passage through the SRA modeling process. The same data points used to customize each Craz² for specific components are taken in aggregate to characterize the archetypal component that SRA built Scuttle to serve. Kevin put it this way: "We used a model designed in house, which targeted the most common vibrational challenges found in a typical high-end setup, based on percentages. We call this process 'problem averaging,' and the results are very predictable."

SRA tunes a Craz² rack within a narrow range for the specific weights it will support, so it makes sense that the Scuttle is actually more forgiving. Not only did SRA perform extensive vibration analysis on the Scuttle, they tested electronic signal distortion output by sets of low-end, mid-level and high-end equipment with and without Scuttle in the chain. Kevin observed with confidence: "We have a very good idea of what the sound will be when the customer installs a Scuttle in his listening environment."

A rack is a rack -- unless it’s a vibration-control system

t first glance, the Scuttle looked like a well-proportioned piece of furniture with a hint of understated industrial yet décor-friendly elegance that should garner high wife appeal. Looking deeper, I discovered a host of vibration-control technologies designed to work in concert as a sophisticated isolation system.

Consider the skeleton of a three-shelf Scuttle. Unlike a basic audio rack with rigid structural elements, the Scuttle’s frame is actually part of the overall solution. It causes vibrations acting upon it to do work and dissipate. The frame comprises two end pieces and three shelf supports. SRA builds these from very thin layers of carefully selected hardwoods and softwoods, precision cut as whole pieces on a CNC mill. The pieces are laid up in a specific order with each layer glued to the next using three types of viscoelastic adhesive. When vibrations run into something viscoelastic, they attempt to move it -- to push around the molecules of the material. The resulting molecular friction absorbs the energy of this movement, then the "stretched" viscoelastic material springs back to its original shape, converting that energy to heat, which gets passed on to neighboring viscoelastic material and finally to the surrounding structure.

As you might expect, custom-designed viscoelastic adhesives and coatings are a house specialty at SRA. Their use reflects another aspect of the Scuttle’s similarity to the Craz². That rack's internal skeleton of alloy tubing retains similar compounds, while the wood in the Scuttle’s frame plays the part of the bread in a multi-layer viscoelastic sandwich.

The outside layers of each frame component receive a distinctive coating of a black phenolic composite that adds considerable strength. Once on the frame, SRA machines this resin to a specific pattern; up close, it appears slightly wavy and random. The pattern helps frustrate the tendency (known as skin effect) for vibrations to travel freely on smooth surfaces, growing in amplitude as they gain momentum.

Where each end support meets the floor is a black footer cap holding an adjustable spike. With three shelves in place, the 250-pound mass of a spiked Scuttle offers a secure platform for audio gear. Each footer assembly decouples its spike from the frame to help isolate the main unit from floor-borne energy. The end supports also hold the shelf supports in place via SRA’s blue isoBushings. These decouple the shelf supports from the end pieces, allowing them to float.

In fact, the entire Scuttle framework enjoys 6DOF, or 6 degrees of freedom, meaning it can flex freely in any direction. To help keep it from racking out of ideal square, SRA fixes three horizontal beams of gray composite material to both end frames at the back of the rack but not to the shelf supports. With shelves in place, I barely saw the gray beams.

The Scuttle’s shelves sit on black isolator pads mounted on the composite crossbeams attached front-to-back on the shelf frame. On a wide Scuttle there are three of these beams, each able to flex independently based on load. The pads create the connection between the highly damped Scuttle framework and its shelves, without changing the vibrational characteristics of either.

The black isolator pads are a combination of two materials joined by another in-house-designed viscoelastic adhesive. The lower section of the pad couples to the rack yet decouples at contact with the shelving unit. I speculated that these pads were the functional analog of the Craz²'s component-tuned isopods, with a broader weight tolerance.

I asked Kevin about the pads’ unusual design: "The shape is a little more complicated to explain, but simply: a vibration (or anomaly) will oftentimes travel across an object, gaining momentum along the way, but round objects (or disks) are very interesting. If the design of the material is just right and the implementation correct, vibrations moving over a disk tend to meet in the middle, causing somewhat of an overload, which results in a significant loss of vibrational energy. The small 'bridges' between each disk limit the surface area remaining for energy to travel."

The Scuttle employs ¾"-thick shelves made of the same SRA-engineered material used for Craz² shelves. Their high-end look suggested they could be granite or maybe soapstone, but the shelves were much more exotic. SRA forms them from a dense composite of spherical nanoparticles existing in an irregular void-matrix of tiny vacuum pockets. The shelves absorb energy from components and defeat its spread elsewhere. You already know what happens when sound meets vacuum. I expected Ripley from Alien to appear and scream at my gear, "Onboard Scuttle, no one can hear you propagate."

Digging into Scuttle's construction made it clear to me that no detail went unexamined. In building the Scuttle, Silent Running Audio undertook a systematic quest for affordable perfection. From footers, to frame, to pads, to shelves, "Scuttle's effectiveness is not based on any one part; it’s an orchestra," remarked Kevin. In effect, the entire rack is a constrained-layer isolation system. "The sum of all of these parts working together as one, also allowed us to control the 'Q' (i.e., the sound) of the rack itself. All SRA products are designed so as not to add any 'flavor' to the musical presentation."

A detail invisible to the eye is product longevity. Some audio racks become less effective as they age -- for example, Sorbothane deteriorates and welds suffer stress fatigue. SRA’s position was impressively clear: "We will never use a material that degrades over time." Scuttle components are designed to work together forever, and SRA offers a lifetime warranty to underscore this.

The Scuttle has landed

t was 9:30 at night when I sweet-talked the lady at the local freight office into sending a guy over to my house with a pneumatic lift. I felt lucky that someone answered the phone. It turns out that delivery of the Scuttle happened a day before it was scheduled with no one at home to open the garage. There was the 300-pound carton sitting exactly in the middle of my driveway. It was sleeting and a layer of ice coated everything. So it goes in the backwaters of reviewerdom.

Kevin had e-mailed precise instructions for unpacking the Scuttle. Its large shipping crate was well marked to match his directions. I could tell he had done this before. After removing the labeled screws, I pulled off the top and front panel as a single unit. There sat Scuttle, snug in its box, perfectly intact and completely assembled.

After removing the retaining wrappers, I carried each shelf into the bowels of Schloss Aucremann. Next, I slowly tipped the Scuttle carton onto its back to await morning and the arrival of Number One Son.

Next day, we each took one of the Scuttle frame ends and hoisted it up and out of the crate. Gingerly turning the rack right side up, we carried it downstairs to the listening room. Be advised: stairs or not, if a Scuttle comes to your house, count on having help to remove it from its crate. My assistant left for work with a nice tip.

The Scuttle arrived with spikes attached, so once on carpet or wood I could only move it with all legs off the floor. Slipping a small furniture dolly under one end of the rack, I lifted the other and steered it just so into it its final position on the side of the listening area. A 9/16" wrench fit on the spikes to level the frame. After carefully positioning the shelves on the isolator pads, I double-checked each with a level. The Scuttle looked good, and I gave it a day to settle.

As I broke down my system to move it to its new home, I surveyed the hodgepodge of vibration-control add-ons I’d acquired over the years. Integral to the design of my Teres turntable were three Stillpoints footers. The Teres turntable rested on a thick piece of maple block, mounted on pads of cork sandwiched between corrugated pieces of hard rubber. The Ayre C-5xeMP digital player sat on Symposium Rollerblocks. The native feet of the Audio Research Reference Phono 2 rested on another large block of maple. Under other components were brass cones of various sizes and styles. My mono amps sat on locally made wooden stands spiked into the floor; the amp stands held heavy plinths supported by Sorbothane pods. At one point, I had a cheap black audio rack with composite shelves and a steel frame, but I banished it to the land of ugly things.

I utilized these devices in a somewhat ad hoc fashion, trying this and that and occasionally switching them around. For the most part, they were a pain to install, and I struggled to balance components on them securely. A few of their purveyors spoke of "mechanical diodes" and "draining energy," but it was never clear where all that drained energy went.

The maple block under the Teres turntable improved the bass and lifted the entire soundstage off the floor. When I placed my ear on it and wrapped with my knuckles, it was obviously very resonant. Originally, I bought the Rollerblocks for use under a Parasound CD player -- they slightly sharpened transients and images, and gave a modest slant to the upper frequencies that at one time I found appealing. To tell the truth, I was never certain what the brass cones did, although I had a suspicion they were exposing more of a component’s underside to airborne vibration.

All in all, I figured these various items were tuning the sound of my system, not returning its signal to an unaltered state. I had never taken a systematic approach to isolation. Except for the Stillpoints, none of my accessories had a particularly significant impact that I could not live without.

With that, I moved my gear to the Scuttle. SRA strongly encourages all gear be placed directly on the Scuttle with no intervening accessories. When I set up my analog rig on the Scuttle’s top shelf, some neuron failed to fire and I installed the motor controller for the Teres Verus rim-drive onto the same Walker cones and Art Audio Q-Dampers that I’d used for years. I’d always used a VPI brick to keep the motor controller from being moved around by its thick Shunyata Research power cord. Aside from the occasional ground-loop-hum in a review component, that controller has always been the noisiest thing in my system. Whether the 'table was spinning or not, the controller emitted an exceedingly faint but obvious-to-the-audiophile-ear electronic hum.

I was standing there admiring my handiwork when the hum broke through my awareness. That led me to the cones, which I proceeded to remove. I placed the motor controller with its little rubber feet directly on the Scuttle, still using the brick to hold it down. The hum was gone. I started the 'table spinning, but still no noise. I had no explanation. The Scuttle made my system quieter before it played note one.

All your vibe are belong to us

he Scuttle was always on, but its action happened at a molecular level. Waves of sound smashed against my components, while the Scuttle waged its battle on a different plane, staunch like a harbor breakwater taking the pounding, doing its job, wave after wave. I knew it was working -- isolating, dispersing, damping unwanted energy, energy that not only did not contribute to the reproduction of music but actually interfered with it.

There was no straining to hear its influence; there was no searching for the perfect demonstration passage. As I listened to symphonic-scale music recorded in a large hall, the Scuttle fleshed out the full acoustic envelope of the performance. There was no blur, wandering, or doubt about the musicians or the instruments that created music within the performance space, nor about the nature of that space itself. I thought about walking into the soundfield and plotting a principal oboist with a GPS. For the first time, my system offered a proper sense of orchestral scale relative to my room. For the first time, sound from the Wilson Sasha W/Ps, with their ten feet of separation along a 20-foot wall, became utterly seamless as they disappeared within a wholly dimensional soundfield. The effect of the Scuttle was not subtle.

Concert-hall acousticians tell us our ears and brain extract precise information about azimuth (horizontal sound localization) and distance from the phase relationships of harmonics much more so than fundamentals. The ear has a naturally fine sensitivity for using time (phase differences) to localize sound in space. In the concert hall, information scrambled by early reflections leads to a less engaging experience. With an audio system, phase distortion (time aberration) messes with our sense of the reality of what we hear. It moves things around in the space of a soundstage, it changes instrumental timbre, and it blurs attack and decay.

What the Scuttle did was squash the causes of this distortion. It substantially reduced the vibration-incited electro-mechanical hash and jitter that led to minute temporal variations in the audio signal. The differences in signal were, no doubt, measurably small, but the difference in what I heard was magnificently grand. I previously had no awareness of the mayhem wrought on my entire front-end by the very music it reproduced -- that is, until the Scuttle arrived.

In terms of focus, localization and intelligibility, the Scuttle improved soundstage depth and height by an order of magnitude. Soundstage width fluxed within and around the speakers, poking itself out here and there, constrained only by the nature of the recording. I lost the sense of listening to music from a stereo and gained the context of whatever performance was at hand. Within my room, the musically reproduced concert hall became the room, with a dimensional fullness properly proportioned to the space within which my system operated.

Don’t get me wrong -- my gear has always rendered a credible soundstage. The Scuttle simply took this to an enthralling level of verisimilitude. It didn’t change my components; it allowed them to operate unfettered by unwanted energy, as their designers designed them to do. Front- and side-wall reflections became obvious, and individual performers and instrument sections came seriously into focus. Individuals and groups acquired defined spatial relations to one another. Listening to the large choral work "Der Morgen" from Richard Strauss’s Die Tageszeiten (Tutti, [Reference Recordings RR-906SACD]), I sensed how the 150 Turtle Creek choristers were tiered on risers, their song lifting up and out to the sides of the large hall in Dallas’s Meyerson Symphony Center, where it hovered in a cloud of harmonic bloom. That did nothing to obscure the choir’s composition from its individual singers, as I heard rows and rows of distinct voices sharing their song without smearing their individuality as its source.

Conceptually, I knew the notes were there and, with the Scuttle on hand, I finally got to hear the entirety of the back-hall vibraphone arpeggios in Ron Nelson’s "Rocky Point Holiday" (from Holidays & Epiphanies [Reference Recordings RR-76 HDCD]). Reduced signal distortion from each component meant my system’s noise floor fell, while, under the Scuttle’s sway, its presentation of fine detail grew more acute. Also from Tutti, the "Berceuse and Finale" slice of Stravinsky’s Firebird Suite revealed an articulate brush-stroke bowing technique, as violinists lifted notes off strings at the end of phrases. The Scuttle turned every piece of music I played into a sampler of previously unheard sonic delights. The refinement of Eugene Istomin’s sustenuto pedal artistry became obvious as he put his own signature of sustain and release on the achingly gorgeous Mozart Piano Concerto No.21 [Reference Recordings RR-68 HDCD]. Listening to well-known selections brought fresh musical appreciation for performers and compositions alike. That alone was worth a ticket to ride the Scuttle.

Digitally sourced music no longer created quite the same level of apprehension or tension -- that sense I sometimes had of friction among musical pixels too tightly wrapped. With the Scuttle doing its thing, the music’s character seemed less mechanical, more at ease or at home with itself. Choose your own expression as you prefer, but my ears could not deny a more relaxed, un-self-conscious listening experience with the Scuttle in place.

As I looked over my nightly listening notes, I found them littered with exclamations of discovery about the improvements I heard to the system I already had. My analog rig was no exception -- with the Scuttle for support, it never sounded better. When I rapped on the Scuttle’s top shelf with a record playing, there was zero amplification of my knocking, and this seemed to translate to records themselves being quieter.

Careening to and fro, the drunken sailor that is Ravel’s La Valse swayed into my room as I spun up one of the very best recordings from the Mercury Living Presence series [Mercury SR90313]. The music was brilliant, "the apotheosis of the Viennese waltz," it seemed to exclaim as it lurched about with a rhythmic devilishness that even Stravinsky could admire. I was a bit staggered myself as I heard what happened when a pretty decent system played a really good record under the influence of effective isolation.

In the past, the undercarriage of this tune could sound a bit like a flaccid mattress, giving its soloists a jouncy ride across the measures, but not this time. Opening bowed basses had bite and crunch; I heard their attack couple with a newly revealed tonal richness. As a rhythm section, the entire orchestra sounded more alive, the air in Cass Technical High charged with vibrant energy. Fifty years had passed, but each musician was holding firm in place. I heard a breathy flute glissando, which previously had a bit of a wheeze to it, sound with note definition and true flute tonality. Tambourines, their clappers clear and distinct, cut through the air just like in the concert hall. Not only their direct sound, but also the reverberant reflection of trumpets was golden and defined. I could sense the air moved by massive bass-drum wumpfs, and thwacks took a sonic bounce off the venue's back wall. The edges of timpani strikes were crisp and their notes varied in amplitude and attack. The Scuttle brought all its virtues to the analog show, and my ears were happy for it. Ravel never sounded better.

Across the board, from timpani to bass guitars to cellos to kick drums, lower frequencies were clearer, tighter and deeper. I was surprised how well I could follow Guy Pratt’s bass solo after the drums kicked in on Pink Floyd’s "Dogs of War," from Momentary Lapse of Reason [Columbia OC40599]. This raucous song really tightened up, losing what I previously heard as confusion or blur during peak sections. When the tune’s many forces came on strong, the contributions of each were impressively clear and well parsed. Once again the contributions of the Scuttle were obvious.

Get thee to a Scuttlery

ibration control is not an accessory, nor is it the final frontier -- someplace you take your system to finish it. Outside an isolation context, audio components will never tell their truth and the music they reproduce will always be distinguished from the real thing. I’m tempted to argue that an effective equipment rack is a required component in any audio system, but having effective and affordable vibration control made widely available will go a long way to making that case on its own merits.

With the Scuttle, Silent Running Audio has given us that. Each Scuttle configuration has generous room for the number of components that SRA designed it to support. The choice of materials, the professional fit'n'finish, and the tasteful good looks make the Scuttle an appealing product. While the more expensive Craz² may improve performance, the Scuttle presented no sonic tradeoffs -- it was all upside. Kevin Tellekamp told me that they are selling like hotcakes, and I know why. The Scuttle delivers stunningly effective vibration isolation at a price that brings a high level of functionality to a much wider audience.

Frankly, I had no idea my system was as good as the Scuttle revealed it to be. With over thirty years of being an audiophile under my belt, the satisfaction value of that is so rare that I have no desire to measure it. The SRA Scuttle is the first piece of gear I feel confident to recommend if your system lacks serious vibration control. Beyond its analysis with audiophile words, beyond its design and build quality, the SRA Scuttle brought me such listening enjoyment that I will not give it up.