This is great information, but unfortunately I cannot use the seismic bars for isolation under my speakers. Only, a solution directly beneath and not protruding beyond the footprint of my speakers can be applied. And, that's one reason why I have the Symposium platforms. I think I will leave my speakers alone for now, because my system right now sounds pretty killer.
Now, that I have solved my sub-to-turntable oscillation problem, I am enjoying the extra benefits of SQ from the isolation bars, so thanks John.
I'm going to do some serious listening.
Kenny