Sand bags under/over For Isolating ?

It works good if your floor mounted on wood joists that make it pretty unstable especially when you play turntable and someone walks by or runs by.
I managed to get away with it placing my rack right onto the corner where my system is less affected by such.

Sand?--an anathema, for what you're considering. Belongs on the beach. peace, warren

Me too! Couldn't remove them fast enough!

Yes. They sound awful in my opinion.