DIY speaker isolation base for a wood floor

Thanks for everyone's help!! I ordered the 8 springs today. They should be here Monday. Ih what fun. Let me put the ideas I have in my head.
1. Use the 4 springs on the floor directly coupled to two 16x16 granite slabs with nothing in between.
2. Same as above but with aluminum cones between the slabs.
3. Same as #2 except the cones on the floor and the springs between the slabs. 
4. Springs on the floor and sorbethane between the two slabs.
5. The springs on the floor with a cork and neoprene sandwich between the slabs.
Ok now which one should work best????? Where's a testing lab when you need one! I'm excited about trying these options. I'm off next week so I should be able to experiment. Again thanks for your input.

6) The one where you get creative and figure out a way to have the springs and sorbothane between the two slabs at the same time ... or maybe the springs and a stack of lightly compressed cork. That way you get isolation and dampening.


Which springs are you getting? If you have them at the bottom, you need the right springs for 125lbs (spring and two slabs). The resonant frequency of the spring is a factor of spring constant and loading.

Oops I don't know. I went by today and they had 6 so I had them order 2 more. I should have taken them home with me. I can call Friday and find out though. This is fine line technical. Thanks.

Should I get conical springs?

If you have large diameter springs and do not overly compress them, you don't need conical spings. Conical springs have better stability the you can make one layer sit within another, but you shouldn't be compressing them that much. It is a bit harder to calculate the operating point for a conical spring.