The principle is that in a suspended turntable the platter will apply a force (torque/twist) to the suspension as it rotates. Some say this gives them their reputation for sounding "laid back" or creates a slight blurring effect on the sound. The bottom platter is there to counter this force and by doing so creates an extremely stable platform that is isolated from all external interference. I don't have enough experience to tell you if the "laid back" thing is true but I can tell you after owning a Sparta and now the Pro the two platter thing definitely works. Both the Sparta and Pro are extremely high resolution, image spectacularly, and are extremely quiet. The differences between Sparta and Pro are the 12" arm, the plinths are sandwich phenolic (vs skeleton), and the platters are heavier with beefier motors. Louis tells me the plinths make the most difference in the sound (and most of the price difference as well). The second big difference is that you can use the SCPS with the Pro. Two banks of super capacitors that switch every 60 seconds and provide ultra low impedance output to the DC motors while completely isolating the table from the power grid. Kind of sounds like a bit of a gimmick when I tell you the power supply makes a major (not minor) audible difference to a turntable but it's true. Anyhow, sound is excellent. If you guys are interested I can do a few needledrop samples; hit me with some requests. I do a lot of LP transfers for my DJ gigs so I am very much looking forward to getting started with these.