Yoga blocks for isolation

Good idea. Ikea sells cork hot pads in the kitchen section which are thin and can be stacked. These work well too. 

Some pills make you larger 
some pills make you small 
the ones that mother gives you
don't do anything at all

Yoga blocks would seem to be well suited as isolation devices. . Can't hurt to try.  

Mapman wrote,

"Yoga blocks would seem to be well suited as isolation devices. . Can't hurt to try."

Actually they don't seem well suited as isolation devices at all.  Maybe you meant to say coupling devices.  Perhaps you might also think hockey pucks, Sorbothane and lead fishing weights are well suited as isolation devices, too. I suspect you might need to investigate the whole mass on a spring concept that's been floating around recently.

cheerios

Try them under speakers on a suspended plywood floor.  It should be relatively easy to determine to what extent they isolate or couple. I suspect more the former but the proof would be in the pudding.