I think the sped-up sound is a psychological phenomenon, not a physical one.
I'm not sure what magnetism has to do with why we don't fall throuh the pavement. If everything were made of classical masses, magnets, and charges, Earnshaw's theorem says that there wouldn't be any stable arrangement. Everything would collapse. In reality, everything is made of quantum objects, which have non-classical properties. The inability of one class of these particles, fermions, to have multiple particles in the same state keeps things from collapsing. We're made of fermions: protons, neutrons, and electrons and so is the pavement.
Mke W.
(published on 08/15/2020)