Granite Bases for Vandersteen speakers

I had granite bases made made for my Quatros  on Richards recommendation they weigh 120 lbs 
The bases tightened up the bass mover it down even lower ,focused the midrange and add more depth to the soundstage you can check out the picture in virtual systems

Enjoy the Music
if we are talking about mine my table sits on my version of a Ginkgo platform the floors in my place are bounce 
thanks Tom....I am pondering them for the 7’s. Helmut Brinkmann of turntable fame was the first to try granite under his 7’s at the Munich show I believe. Most Brinkmann components come w granite bases.
You're right about granite, it does all you say. Yours are custom cut versions of the machinists top plate that have been under my turntable and amp for many years.

Something I always suspected, but it took many years to hear it, granite imparts a hard edge. Always suspected, because hit it and it makes a high pitched ting or tink type sound. So its there, but might be hard to hear right now. It was for me. Meanwhile there's all the benefits you can hear and already described.  

Fortunately it turns out the mass makes a great base for springs, and the springs do a great job of erasing the hard edge ringing. I notice a lot of components still on factory feet. If you want to try a nice improvement, Nobsound springs on Amazon are very cost effective. Meantime, good work!
I wonder if IsoAcoustics footers would work even better, or perhaps those footers on granite would be ideal. I would think just using a granite plate would compensate for a bouncy floor, but at the same time easily reflect vibrations back into the speaker, which you would not want.
Adona equipment racks are made with granite shelves which are then bonded to an MDF layer with an elastomer layer in between. It addresses the ringing that you mention MC. I'm sure that this could be added to any granite slab. 
Constrained layer damping between layers of granite = yes. Note your Quattro cabinet with a cabinet is constructed this way already.
springs, springs, springs wrong answer for a hyper coherent, time aligned, phase correct Vandersteen. Pretty much every other speaker, yes. 

Tom - You and JohnnyR could test the theory w pair of VLR signature on a couple of the HRS isolation bases w springs.... 

have fun, experimenting:-) 
Confirm with quick call Vandy bases built up w 11 pc Granite and proprietary adhesive. 
These things work great. Too bad they are out of stock. Search around, others might have them.

Sorry, did not know Vandersteen were hyper coherent. That being the case springs will work even better. They do nothing to alter timing, just to eliminate ringing.
@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.
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.
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  
Personally I have not tired anything under my Vandersteen 5As those look really nice.
Thanks didn't think about until I heard them on the 7s asked Richard if I could do it to the quatros wouldn't be able to attached to the speaker but could sit them on top
Hi Tom, beautiful system. What is the height of the granite and did you have them cut at a stone yard?
Thanks jaker the bases are 3 3/4" granite slabs are 1 1/4" thick the base is three layers I have them fabricated and I install it through 
Audio Connection in Varona NJ