@noromance :) but you would be surprised how much they "react" to something bad in the chain... In my house in Spain, built on top of rock ground, with rock and bricks and concrete, isolation/resonation is not as big deal as the house in the US. In the US the house is in an island, sand on top of slate(?) 25 feet below.
There a car goes by, and even though I can't hear the car go by, I can hear it in the sound. the road is about 150 feet from my house. I used an iPhone app and it is crazy how the vibrations go to the table. I definitely need something more there.
New racks are coming, hopefully that will help too.