don't do squat to low frequencies , neither do iso pads unless you share the floor.
Piano is loud and percussive with it. You better hope your neighbours like piano!
My through the wall neighbours can't hear my bass practice amp but they can hear if I get too rowdy with the rig. I never hear their TV, just an occasional thump from kid banging around. Gibraltar board multilayer fireproof wall also good for serious noise reduction!