Best TT plinth material, cost no object

It is said that the best material with which to build a loudspeaker cabinet is LEAD, the second best is concrete and the third is Aluminum. Only the third has been adapted by the industry, for obvious reasons.

Internal and extraneous vibrations need to be dampened or eliminated if sound smearing is to be reduced,

Now to the turntable; remove it from the influence of vibrations, internal vibrations not withstanding, and the vinyl should sound better.

Not all of us can put the turntable outside on the sidewalk where only the elements can affect the sound, but can we make the plinth so HEAVY that we can come close to removing the turntable from the sound room entirely?

Can a lead plinth, not too practical, get us as close as possible to putting the turntable outside, on the concrete walk?

Your thoughts, Ken
Hey Lewm

thanks for the explanation. what you hear is what matters. the reason I struck up the conversation was to get a better feel for the background of your experiences. I am 100% in the "what sounds best" is "best" camp, yet I still feel I need to adhere to some type of logical structure for collecting data based on experience.

Always nice to hear that some mini meets are organizing. It is a very positive way to compare and learn from each others, especially in turntable plinths department. Don't forget to report your meet impressions !

Thorens has made the Thorens Concrete, made of... you guessed it!
Dear Intact (Dave?)
I agree with your statement about logical structure. That's why I embarked on the project of acquiring the idler-drive and direct-drive turntables and then making slate plinths for them, so I could hear for myself in my own system. (I also bought a Garrard 301, but I realized along the way that I had no energy left to wade through the Garrard options, plus I grew to love the Lenco, so I re-sold the 301 with no plinth.) Little did I know it would take the better part of two years (of my "spare time") to identify and solve the problems associated with making the plinths that I did make. That's also why I don't feel qualified to make any broad generalizations, beyond slate is "good". Something else might be even better.

I neglected to mention that the Kenwood engineers apparently also valued the idea of Constrained Layer Damping and the use of disparate materials perhaps to spread out the resonances. The L07D plinth is primarily made of the very dense cement-like material described above (if you look at a photo of the L07D, the stuff I am talking about is painted dark bronze or brown and is the major visible structural element), but hidden below and around the motor/platter area we have a sheet of thick stainless steel or aluminum. Below that is a very large piece of intricately cut hardwood (mahogany maybe) which is bolted up to the bottom of the chassis by at least a dozen metric screws that anchor into the stainless steel pan. (The wood piece can be seen peaking out around the side edges of the plinth; it is painted light gray.) Finally, that stainless steel or aluminum piece that surrounds the motor gives off a solid metal "arm" that goes all the way to the tonearm mounting platform, forming a firm coupling between the bearing and tonearm bass, which also contains a very heavy brass anchor-weight. Those guys were not fooling around. When I first acquired the table I had the notion of replacing that hardwood piece with a piece of slate, but it would take both a waterjet AND a CNC machine to re-create the shape in slate, I will leave well enough alone.

Maybe the answer to the OP's question is that it takes a real knowledge of materials science and that possibly a variety of materials used together in a certain kind of "sandwich" would make the best plinth, cost no object.
Dear Ken: This is only my thoughts on the TT subject:

you are one of the more passionate human been in audio that I know and this kind of passion is the " drive " that carry on to a person to achieve almost any target.

I don't know which is your professional career ( studies. ) and maybe the science aplication to meet TT solutions is not a job to one person because it is not only that you have the knowledge but you need a full laboratory to find those TT solutions once and for ever.

So, I think that a institution like an University could be the best place to " fix " the TT questions. It is possible to ask this kind of help/support to these kind of institutions? through a friend that has contact with?.

I don't know it is only an idea because we find here in México ( through a friend. ) this kind of help in our self design tonearm and maybe you could make the same.

regards and enjoy the music,