Soldato
the paving slab is ideal to tighten sloppy bass, if the bass still resonates into the floor then isolate the slab on some specifically designed foam or isolation platform, ideal compression of the material comes into it, and you start heading into mass/spring/mass equations, which gets complex. Ive recommended using paving slabs over selling a dedicated product, and you get better results. Sorbathane feet also help to reduce boom on shelves or cabinets.