Springs under turntable

@frogman 

+1. You may remember me talking about my many experiments with my VPI mkIV.

I ended up using Symposium Rollerblock Jr's in place of the springs. It was a revelation!

Boinnnnggggg.
https://www.efunda.com/DesignStandards/springs/calc_comp_resonance.cfm

Thanks very useful indeed.....

My best.....

This concept of "zero stiffness" is interesting.  I have been reading the paper that was cited above.  It seems in fact to be a theoretical ideal rather than a truly attainable state. But that's OK as a guide. From my experience with turntable supports, the Minus K comes closest to zero stiffness.  If you can achieve what the Minus K achieves using only inexpensive commercially available springs or modified springs, you are a very patient person.  I would still have more than reservations about seating a speaker on a support that had zero stiffness, especially in the horizontal plane.

UPDATE on my nobsound springs adjustment...

The adjustment by adding load is more delicate than i said at first ...

A difference of 2 pounds of load, not 4 pounds, on around 90 pounds of load in total, make a substantial difference in the high frequencies mostly but also all across the spectrum...

A little more than 1% variation in the load is critical....

Keeping off a number of springs from the 7 in the 4 boxes on each speakers would be a too much gross adjustement.... I prefer then with my speakers varying the damping slabs of concrete....For the last tweaking of the load i use 2 plaster book-end on each speakers because they weigh half the weight of a brick, around 2 pounds...

I think that would be very delicate for a turntable, because it is delicate and had take some listening time for my speakers....

One thing is sure, those that think mechanical embeddings makes a not so great difference, and are only an accidental secondary "tweak" would be surprized....

A "tweak" is only a minor addition, a minor refinement when it work; controlling the embeddings is not minor addition, it is a transformative major action on any audio system, be it mechanical, or electrical or acoustical....I am not interested by accidental "tweak" so much, i am interested by the method and the ways to embed the audio system and his parts.....