DIY speaker isolation base for a wood floor

Springs are supposed to be “wobbly.” Springs need only be stiff enough for stability. The best isolation is achieved when the component can move most freely in the directions of isolation. The spring rate (springiness) of the springs should ideally be matched to the load to obtain the lowest resonant frequency of the system.

Thanks Geoff! I had a video of me pushing on it but couldn't download it here.  What are the dimensions and wire diameter that You sell? You are a great resource

So Geoff, do you recommend me doing away with my neoprene/cork sandwich and use my two 16x16 granite slabs?

Pushing up and down on the springs when they’re set up is a good way to measure the resonant frequency Fr of the system. With a stop watch count the number of complete up and down cycles and divide the total by 10. If properly set up you should be able to get down to 2-3 Hz (cycles per second).

I like granite slabs a lot because they are very stiff against bending forces. But I eschew rubbery things in the context of isolation. I suggest very hard cones for mounting and stay away from Sorbothane, cork, rubber, etc. as soft Springy materials store or block energy and interfere with the actual springiness of the springs. Energy should be allowed to exit the system as rapidly as possible. 

audiozenology "Wood floor. Assume somewhat springy? ... then usually better to isolate"

Before isolation I would try to load with mass first it is much more likely to work in that type of situation when using a Music Reproduction System speaker.