Mojo, my whole house is a suspended floor. Built in 1925, about 2.5 feet off the ground,1' thick subfloor covered with 1' thick pine boards.
I am familiar with using granite, slate, soapstone, Corian and sandboxes to isolate equipment. I know all of these "treatments" effect the sound of the equipment, either good, bad or no change.
That's why I asked the initial question, so as to get pointed in the right direction and possibly narrow my experimental options down. I really do appreciate the responses, I is humbling as a new "poster' to have others take the time to think and respond!
