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The following equipment report was written by Shannon Dickson and published in the January, 2000 issue of Stereophile Magazine. The Arcici Suspense Rack A functional equipment rack that emphasizes performance without sacrificing an attractive appearance ranks just below speakers and other core components on the must-have lists of most serious audiophiles. An acceptable stand not only offers an efficient means of arranging the growing number of components comprising today's audio/video systems, but also provides a good focal point for grappling with the deleterious sonic effects of vibration on electric gear - particularly source components. Since I last visited this topic in these pages four years ago (Bad Vibes - November 1995, Vol 18 - No 11), a veritable forest of higher quality anti-vibration platforms, stands, and accessories have appeared. The Suspense Rack, from venerable Arcici Inc., is one of the better examples of improved design wedded to attractive looks to form a solid foundation on which to assemble one's system. Indeed, the Suspense Rack's graceful aesthetics mask some astute engineering choices, and should make it a welcome addition to the décor of many multi-use living rooms. Form and function: Arcici's industrious Ray Shab created the hybrid suspension system for the Suspense Rack by modifying his popular Air Head stand-alone isolation platform. (Similar to products from Townshend and Bright Star, the Air Head was originally designed for Arcici by Texas audiophile Bob Riggle.) |
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At first glance, the Suspense Rack's four clear acrylic shelves seem to be simply attached to the 4 four steel angles that form the vertical corners of the stand--but looks can be deceiving. This outer frame is bolted solely to two open-sided boxes of jatoba wood at the top and bottom to create a rigid structure, but one that lacks the imposing industrial look of typical sand-filled tubular-steel stands such as Arcici's long-established Lead Balloon. The lower, inverted box is equipped with reinforced corners to stabilize the stand, while the upper section--the modified Air Head--contains three small inner tubes that act as air bladders. These provide the vertical pneumatic isolation for the system by floating an acrylic-covered heavy steel plate. The air pressure of each inner tube, and hence the leveling of the top plate and supported component, are adjustable via individual Schrader valves on the side of the box. The key feature of the Suspense Rack's design is that the four acrylic shelves are not connected to the outer steel angles--or to any other part of the frame! Instead, they're suspended from four thin, threaded steel rods that extend up through the bottom of the Air Head and past the inner tubes to attach solely to the upper steel plate via countersunk T-nuts. The corners of each shelf are notched to fit around these loosely hung rods without touching them, while the bottoms of the shelves rest on special Navcom-foam gaskets glued to the top of adjustable "speed nuts" to supply an added degree of inter-shelf isolation. These lockable sliding speed nuts allow easy adjustment of shelf height and level, and are a big improvement over the threaded T-nuts used on earlier versions of the stand. This clever adaptation of the Air Head employs the combined mass of the top plate, the four acrylic shelves, and all supported components to load the pneumatic suspension and lower its vertical resonant frequency to nearly the practical limit for this type of design: somewhere between 6Hz and 8Hz. Furthermore, with the stand's center of gravity suspended below the top plate in loose pendulum fashion, a significant degree of lateral isolation is provided for the entire system--unlike most inner-tube platforms (such as the original Seismic Sink), which rely primarily on the vertical action of the suspension. Deleterious vibration is common in the lateral plane, so effective bi-directional isolation can add clearly audible enhancements over that afforded by unidirectional systems. The lower center of gravity also helps to stabilize the top platform, making it a good location for digital sources and some turntables. Issues of setup and sonics It's not terribly difficult to assemble the Suspense Rack, provided you follow the clear instructions provided, and the robust quality of the inner tubes means that you'll rarely need to add air. Keep in mind that, even though each supported component benefits from the stand's bi-directional isolation, the sonic impact on a particular system will vary based on the inherent vibration sensitivity of the components, their weight distribution, which shelf they're placed on, air pressure, and other factors. Just don't over - or under-fill the inner tubes while experimenting with these variables. I found that leveling the top plate so its bottom edges cleared the upper box by approximately 1/4" worked best with my gear. Be cautious about putting large amplifiers on the same stand as low-level source gear--the proximity of an amp's large power supply to a phono preamp's delicate analog circuits could cause problems. And while the Susepnse Rack's upper platform is stable enough to support turntables with built-in suspensions, stacking one compliant suspension atop another can give unpredictable results. Suspensionless turntables are likely to benefit most from being placed on the top platform. For die-hard analog fans with very deep pockets who want superior turntable isolation, however, I recommend using a Suspense Rack for all digital and line-level components, then springing for a separate solid stand to support a fully active, bi-directional, pneumatic isolation platform such as the Vibraplane, Newport's Benchtop, or Immedia's Noise-Block. Also, as effective as the Suspense Rack is at isolating vibration traveling into the stand, it's almost as efficient at containing vibration generated within supported gear. As a result, the more persistent among you may want to supplement the Suspense Rack with Symposium platforms, Bright Star sand bases, Vibrapods, or other such devices mounted between the components and isolated shelves to help dissipate onboard resonances. But don't go overboard here, and first try the Suspense Rack alone; its design already includes a fair amount of inherent damping. If you're moving up from the average rigid stand or purely decorative equipment rack, the sonic impact of the Suspense Rack alone should be a very pleasant surprise. Based on my experience with a wide variety of gear when all source and line-level components were placed on the stand, you'll likely hear greater openness, and an overall presentation that is relaxed yet more dynamic. I also heard consistent gains in midrange and upper-frequency clarity, resolution of fine detail, and delicacy of rendered harmonics. Image specificity and sound-stage delineation were also improved. Any reader who owns an older Suspense Rack should remove the top plate, deflate one of the four inner tubes that came with older samples, then move the third tube to the front center of the upper box and tack it down with RTF silicone before refilling it with air and replacing the plate. The stand will still support plenty of weight with three inner tubes rather than four, but with this modification you'll experience a welcome improvement in low-frequency solidity and articulation. A three-point support also makes leveling the top plate a bit easier. Whether you're looking for an elegant turnkey equipment rack that will improve the sound quality of your system as much as or more than some electronic upgrades, or are an inveterate tweaker searching for a superior foundation on which to assemble and apply carefully selected anti-vibration accessories to extract the maximum degree of musical nuance from your system, the Arcici Suspense Rack is sure to fit the bill. - Stereophile, January, 2000 PO Box 272, New York, NY 10024 Phone: (212) 579-4352 |