Granite Bases for Vandersteen speakers

@tomstruck, is your turntable on slides? Noromance may be right. This is not a great situation for an unsuspended turntable. I love the fact that you are using a dust cover. Do you have to tip toe around while a record is playing? Any feedback? If you tap on the cabinet while a record is playing can you hear it through the speakers? If not I guess you are alright. I would be worried about adding subwoofers. I see you are limited as to turntables by the size of the space you have. 

Movement in the vertical plane would be the definition of wave launch smearing, best to study up on things not understood.

OP speakers have built in subs, 11 bands of EQ below 120 hz 

I know Agon member, Ctsooner, got marble bases for his Quatro's. 
Hopefully, he can chime in and tell us if it made a difference.
I went with some maple block bases for my Treo's. I can't say they help or hurt. Well, they don't sound worse.
I need to get John Rutan to my place to set things up when I buy the new Sub 3 subs. Perhaps he can do some magic.
Bob

So the speakers are not spiked in to the granite there sit in floor protectors and there is a layer of 1/10th of an inch sorbothane between it and the granite if you put something springs between the speaker and the granite it would be like trying to throw a ball from centerfield to home plate  while standing on a trampoline it doesn't work
Tomic601 i do most of the 7's granite base installs for John there is thin soft layer of material on top of the 7's base and are bolted to the speaker I'm getting about 85 -90 % of the benefit  you will definitely hear 100% the same benefits that I got
I talked to Richard before adding the bases