Magnetic levitation feet

Interesting design.

There’s already many similar products out there.

Here’s one from Triton Audio.

https://www.gear4music.com/Recording-and-Computers/TritonAudio-Neolev-Levitation-Damper-Pack-Of-4/3R... e

Apart from perhaps a minor concern of placing a magnetic field near a cartridge these devices are an intriguing alternative to springs and rubber.

Perhaps these devices don’t get the attention they should. Reviews have been few and far between but here’s one from 2009.

Russell Lichter’s Stereotimes review for
Spikesound Will Isolation Feet asks a few interesting questions which seem to have remained unanswered to this day.


"Now, I understand something of the physics of resonance, how frequencies above a resonant point meet an increasing resistance to and dissipation of vibrational energy.

For example, by installing a small bicycle inner-tube under my CD transport, which weighs 45 pounds, I created a resonant system somewhere around 3Hz, effectively isolating the transport from foot falls, earth tremors, sonic booms and the like.

It solved the occasional problem of CD skipping on playback when a non-ballerina walked through the living room.

But like any simple, under-damped resonant system, it retained kinetic energy. Not ideal.

What happens to the vibration that lies above resonance and therefore does not propagate unimpeded through a resonant system?

Some of it probably bounces back as standing waves and dissipates elsewhere. Most of it converts to heat locally.

In the case of a installation-base/compliant-element/supported-weight system, mechanical friction (typically internal friction) converts motion to heat on a molecular level.

For a relatively undamped, simple system with a single restoring force, the rate of roll-off above resonance is 6db per octave.

This means that if the resonant frequency of a system is 10Hz, a 20Hz vibration will be rolled-off (diminished) by 50%, 40Hz by 75% and so on.

ButSpike Sound Will feet do not have a mechanism for molecular friction; what flexes under external excitement is not a bicycle tube or a spring or a hemisphere of sobothane, but two repelling magnetic fields.

So what happens to vibrations that reach the base that supports the feet?"


http://v2.stereotimes.com/post/spike-sound-will-isolation-feet

What worries me about the Michell is that center post. It appears to fit fairly snugly, but it's hard to tell.

I can see it being extremely effective in the vertical plane. It leaves me wondering how well it does with horizontal or torsional forces. 

Like others, I don't see a way to tune it other than adding mass to the plinth.  And it likely works best when each foot sees the same mass, meaning that one would need to balance the mass of the plinth very carefully. 

Another set from Yamamoto with review here

@vinylzone,

I guess it must be adjustable as most turntable designs attempt to put their centre of gravity somewhere between the arm pillar and the spindle, don’t they?


@chakster,

Good link, again showing just how long these things have been around.

Mark Wheeler has been investigating the relationship between good sound and unwanted resonances over at TNT for many years now - but never in a boring manner.


"Way back in the annals of this vibration control Odyssey I quoted William Blake’s idea that we cannot know how far we should go in any endeavour until we have gone too far and then return to the ideal position. The plebs chorus correctly identified when I’d gone too far and listening proved no advantage despite doubling the spend and pile of shelves."

------

Wha-at?" exclaim plebs, stage left,"The old scribe’s gone too far this time!"

"Indeed your old scribe has gone too far with two Space Harmonisers, four steel cones, four Yamamoto MGB-1’s and four EAR vibration absorbing feet, as the difference is a negligible plus 3 and minus 1 between this and the condition tested in the table (pun alert).

This is neither cost effective nor elegant and therefore not worth the effort."

"The Yamamoto MGB-1 are the best isolation device I have tried with the Garrard 401/SME3012 series I."

Go to this website and all your dreams will come true.

www.Solidair audio.com