the importance of vibration isolation
For as long as I've known, the humble spike has been the necessity on which to mount a loudspeaker or equipment rack, and essential in getting the best performance from a loudspeaker. From a basic point of view, this thinking makes sense - minimise contact with the floor, and hold the speaker firmly without movement.
As always, technology moves on though. And just as there are now hugely more sophisticated programs being used to perfect the aerodynamics of Formula One cars (hence the elaborate wings we now see along with large numbers of "winglets") has moved forward in the field of measuring the behaviour of frequencies and vibrations in various materials, there now exists the ability to monitor and measure small scale vibrations and movements used by the likes of Bowers & Wilkins and KEF, having used such technology to update even their high end loudspeakers, being able to assess which materials suit certain situations better than others, and where to brace cabinets for maximum effect, among numerous other aspects of loudspeaker design. This technology has also been useful for other uses too, including the behaviour of frequencies being passed through a spike to the connecting surface - and what happens afterwards.
Whether your loudspeakers sit on a concrete or suspended wooden floor, the spikes will be hindering your loudspeaker's performance. And it doesn't matter how fancy your spikes are, they all possess the same attributes. Everything has a resonant frequency, including your floor. As frequencies make their way to the spikes, they're not only transferred back up through the spike back into the speaker cabinet, but also across your floor where they meet your walls, then reflect back to be once again picked up by the spike and transferred back to the cabinet. Think of it this way - imagine dropping a stone into the middle of a swimming pool - the subsequent waves make their way outwards to the solid pool boundaries, and are then reflected back to their point of origin. If you drop the stone in near a corner, those waves make their way back at different times, and the nearer the drop to the boundary, the more violent the wave will be when it comes back.
So it makes sense that if you can reduce the transference of sound vibrations to your floor, not only will the speaker see less coming back, but also the amplitude of these vibrations will be greatly reduced. This also has a knock on effect as the vibrations need to get past the isolation again. Some vibrations passed back into your loudspeaker's cabinet can be greater than that of the tiny frequency movements of the speaker's treble unit, so you can imagine just how much these unwanted vibrations can potentially affect the high frequency performance of your loudspeakers.
Similar tests have been done with regards to electronics sitting on wooden/glass surfaces, and this includes high-end equipment stands. To an extent, the material on which your electronics sit can be used to fine tune (even if on a very small scale), but again, whatever the surface, there will be vibrations which will make their way into the product sat upon it. It's very popular nowadays to use IKEA furniture, most of which is relatively hollow, exhibiting different vibrational behaviors to the glass and more solid wood of better built furniture, but still detrimental nonetheless.
There are a few DIY "short cuts" that do the rounds on forums, which will work in a basic sense, but using every day items (such as halved squash balls, which are probably one of the better suggestions) may only have an effect centered around a particular frequency range as they haven't been designed to do the job being asked. The good old Mission Isoplat of the 1990s was a relatively cheap isolation platform option for electronics, but its effects were usually a little hit and miss, probably partly down to having a resonant board sitting between the electronics and the isolation feet!
There are a few of manufacturers now making genuine isolation products that have been thoroughly measured to prove that they perform as described. For this purpose, the little audio company have chosen ISOacoustics. There are products for every situation - from isolating electronics and bookshelf speakers with the OREA feet and Aperta platforms, to the GAIA and GAIA Titan feet designed to replace the spikes on floorstanding speakers, speaker stands, and equipment stands, to the Delos turntable isolation platform. All of these products have been developed using measurements performed at the National Research Council Of Canada.
In depth coverage of the above with plenty of graphs and charts can be read here, for those who want to get into the real nitty gritty of this subject.
Thanks for reading and making it to the end! Feel free to browse the website, email david@thelittleaudio.company or call 0121 638 0721 or 0753 888 1969 for help or to arrange an audition or a consultation. We are a 1 mile walk from New Street Station, or 5 minutes on the Metro system that runs between Broad Street and Wolverhampton.
davidf @ the little audio company