Springs under turntable

Certain engineering evaluations can be solved (approximated) by modeling the behavior as a series of springs and dashpots.

For those of you supporting heavy speakers on springs, do you recommend stiffer or more moderate spring support? In other words, how does the supported combined speaker/stand weight compare to the total available spring loading capacity....something moderate like 50% or something less (i.e., stiffer springs)?

From experience, I would suggest somewhere in the 50% deflection of each spring would be a reasonably safe bet, I know that the tendency is to keep the tweeter (at least) on axis at listening position.

The term I use zero stiffness, stiffness or rigidity here couples the speaker to the support, by removing the stiffness (zeroing it) the speaker cabinet should find it's mechanical equilibrium (where it rests when not energised) and if you can gently move a big heavy speaker with just your pinky finger, you have a pretty good starting point for vibration control.

The spring rate is weight dependent. Weight / number of springs @ 50% compression.
Spring rate is critical, turns is also important, so far I have liked the most, are 3 to 3.5 turns + ground ends on each end of the spring.
I deliberately purchase with the diameter at least equal to or greater than the final load height.
I found that I like a taller spring, my guess is that small amplitude high frequencies are well sorted with more material to deflect them??

Any experts here?

I am not an expert, that was my employer, however I learnt all that I could from him before moving to USA. PM me again, we can go through it together and I'll see if I can get you similar results to MC.

About 7 years ago I replaced the 4 springs under my modified VPI TNT with 4 handballs.  It was a solution that VPI had used on its last TNT version.  Great improvement.  If I could not integrate them into the TT, as was possible with the TNT, I would build a platform with them them a la Ginko.

Only small issue is that they need replacing about every 4-5 years.  

If the Nobsound springs do not work out under my 401 I will try them under my Spatial OB speakers.
One reason I ordered two sets... Options.

The nobsound makes no negative audible effects under my speakers... But adjustment is all the job and the most important...

I think around 45- 50% of compression with an adjustment by ears with 4 or 5 pounds of varying weight or around 4 % of precision near the optimal compression will do the job....It is more refine adjustment and more easier to me to put load on the speakers than removing some springs....And i prefer my speakers damped anyway...