For a cheap alternative, try your local hardware store. Rubber grommets, o-rings, and various rubber thingies (technical term) in the plumbing department can give you a low-cost way to try various decoupling/resonance damping schemes. I've found all kinds of different thicknesses (or double up with several) and levels of squishiness (another technical term). Good luck, Dave
Speaker shock absorbers
From time to time people have posted different methods for mechanically decoupling their speakers from the floor to reduce vibration. Some of these have involved using a ply system of rubber strips and wood strips, which seems reasonable to me. I have looked for suitable sized sections of rubber or even for large sheets to cut up but have been unsuccessful. To those who have used that method -where did you find the material and what thickness of rubber and wood did you use for each layer - finally how many layers did you end up using?