Just ran across this thread- The reason is that the Sota has a spring suspended subchassis with a low fundamental 'bounce' frequency, of about 2HZ; this makes it nearly immune to high frequency vibration, but vibration at or near it's fundamental can send it into resonance. The soft rubber feet are themselves springs, so the whole table has a fundamental that's undesirably close to the fundamental of the subchassis. With the table base on cones(preferably threaded in tight), on a rigid support, only high frequency vibration reaches the suspended subchassis, which it can easily deal with.
To demonstrate the resonance effect, take your table for a ride in a car, which is suspended at just about the same frequency as the table; it will go NUTS! Unless you lock down the subchassis, of course. Or don't risk damage, I've done it, so you don't have to.
To demonstrate the resonance effect, take your table for a ride in a car, which is suspended at just about the same frequency as the table; it will go NUTS! Unless you lock down the subchassis, of course. Or don't risk damage, I've done it, so you don't have to.