There are several categories of audio-feet. The first type is the hard cone, initially designed for use under loudspeakers – the now familiar carpet-piercing spikes and the original Tiptoes. Later applications included supporting equipment shelves and components directly. Hard cones ideally have no compliance, and mechanically couple (rather than isolate) an object securely to the surface below. Thus hard cones should be used in sets of three, as any surface irregularity will allow wobble if four or more are used. The properties of hard cones vary with geometry and materials (including aluminum, brass, steel, carbon fiber, ceramic, and graphite). I tend to try hard cones under components which themselves produce vibration, as the cones will "drain" the vibration away to the larger supporting mass 9the shelf, stand, isolation platform, or floor). Anything with a motor, transformer, or speaker qualifies. In some cases, using marbles or ball bearings is worth a try, as they allow horizontal compliance but not vertical movement. For example, Wilson- Benesch uses small ball bearings between the double plate glass shelves of their ultra-high-end turntable support tables. (Primyl Tip: to keep the balls from rolling merrily about, cut a hole in a small piece of foam (I use air conditioner filters) thinner than the diameter of the spheres and stretch around the ball.) Hard feet tend to affect the "speed", dynamics, and clarity of the sonic reproduction.

A second category is the Tuned Footer. The reason hard cones are made in so many different materials is that each substance has it’s own resonance characteristics, which affect its performance. Some footers are designed around these properties, to "tune" the vibrating system. The famous Mpingo disks (the name is actually an African term for a particular species of ebony) and Combak feet are examples, as are the composite constrained layer damping Marigo footers, and devices using springs or air bladders. There may be both science and snake-oil at work here, but I’ve heard some strange claims validated experientially. Tuned footers can affect the timbral and spatial characteristics of the sound, sometimes making the presentation subtly more "natural".

The third category is the range of absorption/isolation products employing high-tech materials like Sorbothane, Navcom, Norsorex, or other rubbery polymer – or low tech materials like sand or lead shot. The Audioquest, Audio prism, and Deflex pucks, pods, and (hemi)spheres are examples, as are Andy Bartha’s lead-and-caulk Whatchamacallit muffins, Blue-Tak and Mortite, and Bright Star’s sand boxes (think of them as one big footer). The idea is that vibrations cause the molecules or grains in these non-rigid substances to move about on the microscopic level, converting the unwanted energy to harmless heat. Being compliant, four or five (one in the middle) may work better than three. Those seeds-in-a-balloon "Anti-stress" squeeze balls are a favorite cheapo alternative. Absorptive footers tend to smooth out the sonic signature, in my experience.

All the above are worth exploring, but the foregoing has mostly been by way of introduction of a new isolation product – the Vibrapod – which uniquely has aspects of all three categories in its design. It’s also the product of serendipity, and therein lies an interesting tale. Sam Kennard, the manufacturer, is a Primyl Vinyl subscriber and a way-serious audiophile. He owns a company in St. Louis that makes various sub-contracted plasticky doohickeys, and he treats his employees (and himself) to a higher standard of workplace music reproduction than many might have at home. Hell, he’s even hired ex-audiostore employees to work there. So one day he notices that the shop’s CD player, which sits atop some machinery, is skipping whenever the big oven operates. On impulse, he sticks a couple of the widgets or whatever it’s making under the player and – audeus ex machina – the things plays flawlessly. Thus began the development of the Vibrapod, several iterations of which he’s sent to us to evaluate, and which now has become a real product.

The Vibrapod is a 2.5" plasticky doohickey itself, of a shape that’s hard to describe, so the pictures may help. As with cones and balls, the geometry is important – here the component is supported by the 1 ½" dia. Top ring, although in cross-section this is revealed to be an arch, a structure with interesting load bearing/transfer characteristics (which is why they call it architecture, not pillaristics or wallology). The inner edge of the thin walled circular arch is supported by a vertical cylinder of somewhat thicker dimensions, the outer edge buttressed (sorry) by a much heavier, sloping ring – i.e. an asymmetrical arrangement. The inner cylinder has a floor with a small hole to facilitate attaching it. The top ring, being thin, flexes under load, much as a radial tire is designed to bulge as it meets the pavement. And like a tire, the Vibrapod is tuned – the instructions suggest using one Vibrapod per 2.625 lbs. or so of load (or 1.2kg, if you are into metric). They also suggest placing them around the periphery of the shelf or component to be supported, not the middle, but one can feel free to experiment – the things are dirt cheap by audio standards, at just $6 apiece. The tuned flexing is part of the system, as the soft plastic also absorbs energy – but since the plasticizers can affect adjacent surfaces, Kennard suggests protecting vulnerable finishes with sheets of inexpensive stationary store acetate.

I’ve had a lot of fun with the Vibrapods. The hole in the base made for easy direct fixing to several components like the tape deck and phonostage. For items needing more ground clearance, the holes allow combining two back-to-back with a small nut and bolt – I used steel fender and/or neoprene washer in between to add stability. I also tried stacking plate glass/pod/glass/pod sandwiches to put under a component (Manapods?) as well as simply putting them in place of feet. I used a bunch around the periphery and three near the bearing of my Well-Tempered (leaving the motor assembly sitting directly on the marble base I have under the turntable. So, do they work? Yes, but like any of these tweaky things, the audible effects vary from one component to another, but are reliably cumulative. I find the Vibrapods make the overall presentation slightly more "relaxed", dimensional, and less fatiguing – exactly what the expensive ones are designed to do. But you’d have to try them under your own components, in your system, and make your own call. Different feet=different sound. Bottom line for me is I can put them under all sorts of things I could never justify using the $20 per foot variety. The tape deck, tuner, DAC and jitterbox, stepup transformer, even the power conditioner can now all get the same attention as the preamp and source components.

Jeff Bellin has also tried out some Vibrapods, and provided Primyl Vinyl his own assessment: