@clearthinker , the earth is not a solid ball. In actuality is is more like a pile of sand, water and molten rock. Sound waves travel right through the ground and your concrete slab. As any New Yorker what happens when the trolley passes by. You can feel an earth quake miles away from the epicenter as it travels in low frequency sound waves right through the earth. Put your stylus down on a stationary record, turn the volume up and watch your woofer. Jump up and down and see what happens. Hit the cabinet your turntable is sitting on with a soft mallet and watch what happens. Have somebody open and close your garage door while you watch.
"Assumptions are the mother of all F--K Ups."
I am far from the only person who understands this. Standout personalities that do were/are Edgar Villchur, Mark Dohmann, David Fletcher and A.J. Conti. Suspended tables are inherently more complicated, engineering intense and expensive. Throwing a lot of mass at a turntable is the dirty way of going about things and it does a good job placating lay intuition. I know a gentleman who had a footfall problem with a Kuzma Stabi XL DC. He cured it by placing the rig on a MinusK stand. My guess is you do not have a foot fall problem but plenty of other low frequency rubbish is getting through. Anyone with sub woofers playing vinyl knows this for a fact. Most of the rubbish is on the record but, some is not. Very little is coming from our modern belt drive and direct drive turntables.