A Brief Survey of Isolation Devices

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It’s unquestioned that vibration and resonance alter the sound of our playback systems. How to deal with the problem though, is a topic of unusual complexity. A myriad of variables combine and interact to make the equation particularly convoluted. Influences include: source of vibration (structure-borne or air-borne), equipment support (nature of rack or stand), and sensitivity of the components to the vibrations present and the ability of the listener to perceive the effects of these variables. Include the most important and subjective, ones own personal preference, and we have an equation with no universal solution.

With such disparity among systems, environments and listening preferences, how can a comprehensive, tell-all review be written? It can’t. That’s why this treatise is labeled a survey, rather than a review. The information offered here is but general overview and should be considered a starting point rather than an endpoint.

Most of you have experimented with isolation; be it cones, spikes, bearings, isolation platforms and bases or one of the many viscoelastic feet, they all change the sound. Which one is best, depends on the variables we’ve discussed previously, as well as (and certainly the most important constituent) our own personal preferences. An example: device “A” offers a slightly warmer flavor while device “B” results in a faster or brighter sound. Which is right will depend on your inclination and how your system is tuned. Now, I’m not saying that all isolation devices affect tonality, but the same analogy would apply to other characteristics of the device(s) employed (detail, leading edge transients, ambience retrieval, etc.).

System variables not withstanding, I’ve found that most all devices have a general thumbprint, a basic character apparent in nearly all systems. Many fine points will vary, of course, but I’ve had enough experience with the offerings (both in my systems and feedback from countless clients) to feel comfortable generalizing.

Lastly, I’m neither disputing nor endorsing the concepts or theories behind any of the products. I have no training as a mechanical engineer or physicist; I’m simply a careful listener. I do know there are as many questions as answers in this arena, each manufacturer asserting the validity of their particular designs. So, like with any other product in audio, let your ears be the judge. I’ll offer another caveat. While I have evaluated all the products listed here, I cannot say that I am familiar with every offering in every the line. Further, there may have been changes or additions since my last experience. Again, use this not as an absolute reference, but as an overview to familiarize yourself with available offerings. Always consult a knowledgeable dealer for specific recommendations that suit your system and preferences.

Data is provided in tabular form for easy cross referencing. To keep the survey brief, I’ll offer a basic thumbnail sketch of each product  (though I could write pages on each describing intricacies I’ve experienced, most of that knowledge is specific to my system and may not manifest itself in yours). Next, I’ll grade each product on several scales. I’m trying to stay very objective with these, using mainly feedback that I’ve received from the field.

In the performance field note than some products are tagged with a plus or minus symbol. The “+” indicates a product works well in most systems, “-“ means the item is system dependant, either because of strongly variable performance or mechanical considerations (e.g. too tall to fit in most racks).

Products have been divided into five categories, describing their approach: Viscoelastic (soft resilient feet), Rigid (usually cones of various materials), Roller Ball (devices utilizing ball bearings in some way) technology and Bases (platforms of any sort) and Other (either using multiple technologies or not fitting into any category listed above). Products are assessed using a scale of 1 – 10.

All items are listed in alphabetical order and not in any sort of preferential ranking.

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