"KronosÂ’ variation on the theme is to rotate their second, identical, 30-pound platter in the opposite direction of the main platter spinning the record. In essence, it completely cancels any vibration induced by the first."
I took this quote from one of the reviews cited by Raul. I believe it is incorrect. I don't see how the equal and opposite rotation of the bottom platter could "cancel any vibration". It might cancel some vibration (and it might introduce new sources of vibration), but what it could cancel is the effect dictated by Newton's Third Law of Motion: For every action, there is an equal and opposite reaction. Forces exerted on the motor and plinth opposite in direction to those exerted on the platter by the motor could/would be counter-balanced. This would obviate the need for a massive plinth structure and could be a "good thing", but it does not cancel all vibration per se. I would be very curious to hear it.
