Turntable isolation, without the mythology

A stylus is reading grooves measured in microns. Anything that moves the deck relative to the record ends up in the sound.

Three things genuinely help. First, get the deck off a flexing shelf and onto something with mass. Second, decouple that mass from the surface below it, so floor vibration is absorbed rather than passed on. Third, move the deck away from the speakers, and never put it between them on the same surface.

A heavy hardwood riser does the first two at once: the mass resists movement, and the pads underneath break the path from floor to plinth.