Vibration can be detrimental to the performance of any audio system. Achieving perfect placement of your components isn’t always possible, especially in a domestic environment where rooms are rarely designed around the hi-fi. Airborne vibrations, vibrations transmitted through the floor from the loudspeakers and even vibration transmitted through the audio rack from one component to another can all compromise the performance of a system, sometimes significantly. Naturally mechanical components such as CD players, turntables and even cassette decks are the most susceptible, but the performance of digital components and amplifiers can also suffer in some situations.
The audiophile market is awash with products designed to minimise vibration. Many feet, pads and platforms exist from the sensibly priced to the ludicrously expensive. All claim to improve performance – some claims based on actual science, and, of course, a few based more on opinion and assumption than true fact. However with a little effort it is possible to construct your own isolation platforms for your components which can outperform some significantly pricey alternatives, proving that you don’t have to spend big bucks to achieve excellent results.
An isolation platform is a base material onto which your component sits. The base material is isolated from its supporting shelf in such a way that the vibration entering the platform is reduced, and any vibration caused by the component itself is dissipated. For our isolators, we’re going to use Sorbothane – a synthetic visco-elastic urethane polymer that works by transferring vibrations into a form of heat, undetectable to human touch. Sorbothane is widely used to isolate hi-fi components as well as delicate electronics such as printed circuit boards and disc drives, but it’s also used in rocket launchers, wind turbines and even by NASA. Further reading can be found Here and Here
We’re going to use a set of Sorbothane hemispheres, which are Readily Available Online for very little money. The hemispheres are available in a range of diameters (11, 19, 25, 30, 40 and 50 mm), and it is essential that the correct diameter be chosen for the application. Sorbothane is most effective when compressed or squished within a specified tolerance. The table below shows the correct load ratings:
|Diameter||Height||Load (Single)||Load (Set of Three)||Load (Set of Four)||Load (Set of Five)|
|11 mm||5.5 mm||0.11 to 0.25 kg||0.33 to 0.75 kg||0.44 to 1.0 kg||0.55 to 1.25 kg|
|19 mm||9.5 mm||0.45 to 0.8 kg||1.35 to 2.4 kg||1.8 to 3.2 kg||2.25 to 4.0 kg|
|25 mm||12.5 mm||0.88 to 1.79 kg||2.6 to 5.4 kg||3.5 to 7.2 kg||4.4 to 9.0 kg|
|30 mm||15 mm||2.1 to 4.2 kg||6.3 to 12.6 kg||8.4 to 16.8 kg||10.5 to 21.0 kg|
|40 mm||20 mm||3.3 to 6.6 kg||9.9 to 19.8 kg||13.2 to 26.4 kg||16.5 to 33.0 kg|
|50 mm||25 mm||7.5 to 10.0 kg||22.5 to 30.0 kg||30.0 to 40.0 kg||37.5 to 50.00 kg|
The next step is to choose a base material. Your choice of material is important as its weight must be added to the weight of your component to choose the correct size of Sorbothane hemisphere. My intention was to isolate my Technics 1210 turntable which has a weight of approximately 12.5 KG. I chose a base material of 12 mm Corian which when cut to a 550 mm square to equal the top shelf of my rack weighs approximately 7 KG. That brought the total weight to 19.5KG, which is right in the sweet spot of the recommended load for a set of four 40 m hemispheres. A set of five 30 mm hemispheres would also have been suitable.
A sheet of Corian was purchased. Though great as a turntable plinth, Corian is a hugely expensive material so it’s advisable to find an installer willing to supply an off cut. Mine was supplied by Signature Work Surfaces of Barnsley who were kind enough to cut to the final size and polish the edges, meaning no fabrication was required on my part. The sheet arrived beautifully finished in a custom wooden box to prevent any damage in transit. Packaging of this quality is something I have rarely if ever seen, and the product was delivered within a week. Service of this quality is the exception rather than the norm, and I can recommend Signature Work Surfaces without hesitation.
The setup couldn’t be easier. The Sorbothane hemispheres sit on the shelf with the point of the dome facing upwards. The platform is then placed on top and your component on top of it. Where possible, centralising your component will optimise the weight distribution. Here’s how it looks with a black 1210 and a Corian platform in the Midnight colour:
I was surprised by the performance improvement. It’s fair to say that the isolating feet of my 1210 are a little tired; the springs have begun to sag, and they’re not as effective as they once would have been. My setup also places one speaker in close proximity to the turntable which is not ideal but unavoidable. Those issues coupled to a suspended floor meant that my turntable was often affected by footfall or high volume, but the addition of an isolation platform has solved both issues. A highly recommended and worthwhile DIY upgrade that must be heard to be believed.