Universal acoustics Vibro-Pads Lite

I put these underneath tall living room speakers and the work very well, sound transfer to the floor is gone and they are almost invisible. A bit fiddly to get setup, but once done, you can forget about them.

Awesome indeed!

If your floor-standing speakers are actually on the floor and they are not too tall, these really work well. They're designed for smaller monitor speakers, but I stuck them under my heavy vintage Hi-Fi Sony SS-7200 speakers and they sound great again. And we can't hear the bass in the rooms below anymore. If you have just under CHF 50.- to spare, these are far better than the considerably cheaper (but totally ineffective) polystyrene rubbish that I was using before.

They move a bit around but when you find the good place they really works