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A number of manufacturers now produce isolation platorms which use pneumatic springs to isolate components from vibration. Arcici's own "Air Head" is one such device. These isolation devices are available in two basic configurations: Equipment loaded and pre-loaded. The equipment loaded variety is the less costly type. This provides the air spring mechanism with a minimal weight platform on which to install the equipment. It works quite well for heavy pieces of equipment, but not as well for light equipment (under 20 pounds), because the resonant frequency of the platorm goes up as the weight of the equipment goes down. The pre-loaded type uses a heavy platform above the air spring. Therefore, there is a certain large minimum amount of weight which will be suspended. This guarantees an acceptably low resonant frequency with even the lightest component, thereby ensuring good isolation. The SUSPENSE was designed to use only one three-bellows spring system. This heavy-duty unit is installed under the top shelf. The lower shelves are suspended from the top shelf by four rods, (which are hidden by the frame of the stand). The combined weight of all of the shelves and the rods is nearly 135 pounds, almost exactly the same as other pre-loaded systems. Additionally, because the weight of all the components on the shelves is added together, the total suspended mass of the Arcici SUSPENSE will actually be greater! |
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The SUSPENSE uses four (or optionally more) acrylic shelves plus an acrylic-buffered steel plate weighing more than 70 pounds. The acrylic buffer completely eliminates audio band ringing. These shelves are individually decoupled by means of Zorbex pads under each shelf. This prevents resonant crosstalk between components within the rack - a unique feature among racks. A further design improvement is the location of the center of mass below the air springs. Isolation platforms, whether or not pre-loaded, have their center of suspended mass above the bearing. This makes the platform unstable, requiring frequent "tweaking" of the air pressure to keep it level and allows lateral sway under vibrating conditions. The SUSPENSE, however, with its "plumbline" suspension, is inherently stable. Gross pressure variations which would result in huge level imbalances in a platform, produce only minuscule tilting in the SUSPENSE. The rubber bellows used in the SUSPENSE are virtually leak-proof and require infrequent adjustments.
PO Box 272, New York, NY 10024 Phone: (212) 579-4352 |
