So Brad, what do you think of my conversation with the designer of a well respected audio passive rack system, that lab grade active isolation is superior at protecting eg a tt from floor- and air-borne vibrations, but not great at dealing w the vibrations created by the tt itself?
Ie no gear that active isolation is designed primarily for eg electron microscopes produces anywhere as much movement and noise as a tt w massy spinning platters, moving arms and undulating styli
His argument was that active isolation was never designed to deal w gear purposely putting out vast amounts of vibration pollution
And that gear like tts needs tech that deals w vibrations emanating from the tt itself, preventing it feeding back to the tt
He contends active isoln doesn't fulfil this requirement anywhere nr as well as sorted passive systems
That is a rather interesting conversation. Whether a suspension is active or passive I am not sure how much vibration it is dealing with from the thing it is supposed to isolate. Generally the frequencies suspension systems are designed to deal with are low frequecies (in the few Hz range) but the vibrations being generated by a TT or electronics are signficantly higher in frequency I would imagine (33.3 RPM for some rumble or sub harmonics and harmonic of this rotational velocity) (50 or 60Hz hum and harmonics from power supplies) and those will not be addressed by the isolation system to any great degree...at least not an air/elastomer suspension or active electronic one that is supposed to work at low frequency. This is why I was thinking that the platform you set the TT on could be absorbing those frequencies if you used sand/shot/kitty litter...or as I found in a patent application:
"Preferred granular material is low density polyethylene and glass microspheres. The granular material fills hollow structural members or is placed into intimate contact with open structural members. The lightweight fill effectively damps vibrational modes without excessively increasing the weight of the structural member"
I have speaker stands that are sand filled that I used to use with my Reference 3a Master Control MMC monitors and it added a lot of mass but damped those steel tubes very effectively. It seems lighter materials work too.
Silcone (like used in bathroom caulking) can work as well in smaller spaces but it would take a lot of it to fill large tubes.
Most vibration control is designed to protect the thing from outside interferrence and not from the thing itself. Only something that is good at absorbing vibration over a broad frequency range will work with electro/mechanical devices and that would be something like sand or similar. I remember there was German brand called Clearlight Audio that made some interesting racks and shelves with a proprietary wood based (I think) damping material.
http://clearlight-audio.de/
unfortunately, only in German.
Here is the google translate explanation of their technology.
"
What is RDC?
This RDC (resonance deadening components) consists of a mixture of different fine granules such as rubber, quartz sand or acrylic. Depending on the mixture, the density and structure of this material will change and produce a finely stepped damping flexibility.
If disturbing energies are forced into the RDC substance, then these vibrations must pass through each individual granulate particle, whereby the direction and density are constantly changing and the energy finally dies.
This is achieved thanks to RDC with a comparatively low mass expenditure. The different material densities also lead to a uniform attenuation over the entire frequency spectrum.
The information on the load capacity of the individual cones is intended as a guideline, which should serve to ensure that your installation areas (floor tiles, parquet, etc.) can not bear any damage."
They build it into their platforms and racks, make tonearm headshells out of it (I need to try this now that I see it) and turntables with a bunch of the stuff.
"The RDC rack panels are spiraled on the underside with RDC material. For the top level, a complex sandwich plate with two counter-rotating RDC coils is used."