Hammacher Schlemmer has Kronos $28,000

I just thought of something, in a space ship, the whole space ship would rotate counter-clockwise, if you bolted the turntable to the ship structure, and given sufficient motor torque to overcome inertia.

"Fly me to the Moon", indeed.

"Kronos’ 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.

Peter, I may be wrong, but I think the counter-rotating platters would have a nice stabilizing effect, rather like a gyroscope, but not actually gyroscopic. I am gratified to see that the quote from the designer, "counter-rotating platters cancel the tendency for the plinth to rotate in the horizontal plane around the axis of the bearing", is another way of saying what I wrote above. It's the Law. However, the execution of the idea is what would determine whether the results are worth the added complexity. Which is why I'd love to hear one of these tables.

Would be cool to do a direct drive with counter-rotating platters. DD would be better suited to this concept than belt-drive, IMO. (This is not to take a shot at BD; it's just that BD requires those two external motors and the associated drive belts, which might serve to reduce the possible advantages of this particular idea.)

In an ideal universe there would be no bearing friction. Admittedly, this never happens. But in such a closed system, a force equal in magnitude and opposite in direction, i.e., counter-clockwise in this case, would be exerted on everything that is not part of the platter, when the motor is in action. In the real world, gravity pulls the assembly down on its base, and the friction between the footers and the shelf normally prevents the counter-rotation of the assembly. But the contrary force is present, nonetheless. (This is a problem with spring suspended turntables.) By having the counter-rotating platter of equal composition and mass borne on the same assembly as the functional platter, that force is nullified.

Think about it; in outer space, in a manned space capsule, one could not play a record unless one bolted down the whole turntable to the mass of the ship itself. Otherwise, the platter and the rest of the turntable would both rotate but in opposite directions due to the rotational force put into them by the motor. (Of course, setting VTF would be a bitch as well.)