What should I use between spikes and wood floor?

Linn Skeets

Cone Coaster from Sound Anchors.

I agree with Slappy. My neighbor was putting in new countertops and I grabbed the chunks of finished one-inch pieces of marble from the debris pile. Works great.

I realize that this is not an answer to your question, but I wonder why you (or anyone) wants to couple speakers to a (suspended) wood floor. Personally, I want to hear my speakers not my floors, and I isolate them from the floors for whatever good that really does, which I assume has something to do with the frequencies at which the speaker resonates and whether or not these resonances would excite the resonance modes of the floor. Where have I gone wrong (or have I)?

I used dimes on my hard wood floors, the whole project cost me .80 USD. You can also use pennies if the budget is real tight, or quarters if you want a higher level of performance. All joking aside though, I got this reccomendation from Sumiko audio, and it has worked well for me.