What is the best Vibration
Vibrations come in a wide range. Some are used for lowering metal tubes into soil by shaking the tube with such a force it liqifys the ground, some vibrations are used to transport parts up a slope (or down). And some random vibrations from a membrane create what humans call checks notes music!
My favourite vibration is 12.023hz with a amplitude of 6V in a copper coil!