What is vibration isolation for?


Where do these vibrations come from? From where I stand the earth doesn't shake too badly?! I would think that most vibrations would come via sound transmission through the air directly through the chassis of the components thus rendering the racks or other vibration isolation, uh, useless, no? (with the exception of actual thumping from walking etc)
neubilder
First they put springs under a turntable and claim success. Next they'll be putting springs under automobile suspensions, claiming it makes the ride smoother.

What next?
Anybody here tried one of them new fangled "Levitator" isolation doohickies from www.GR-Research.com/levitator.htm?

Acrylic plate floating in air based on repelling magnets...

Looks really cool but does it work????
I will be more specific - I can understand the use of isolation with mechanical things like turntables(of course), cd players, and speakers, - but people are doing this to amplifiers and pre-amps. I understand the concept of microphonics and that sort of thing, but my point is wouldn't most of the vibrations be coming via the chassis of the component itself - not the table it is standing on?
Insofar as solid state electronic components, the whole vibration thing is bogus to start with. Tubes may be microphonic and a damping ring around them can't hurt, but solid state circuitry is for all practical applications relating to reproducing music in the home not helped by vibration reducing gizmos. You are right in assuming that the music itself will cause airborne vibration to act directly on the chassis. But, hey, that does not stop real believers in spending a bundle to reduce vibration and claiming they can hear positive effects. Geez, folks in these threads keep asserting all the time that they can hear HUGE differences for passive components. Once you start making claims that everything has an effect on the quality of the sound you hear from your system, the slope is so slippery that you can very easily believe that mass loading or isolating with some form of compliant suspension will act on the circuitry. The tweakers will possibly come down hard when hearing this: amp stands et al are a crock. Good listening and don't let the buzzards bother you.
many users laughed at component isolation & vibration control until they tried it for themselves - I was one of those myself, until I tried it.

buzzard