Granite Slabs

I would find a stone masonry company that does work for high quality residential builders.

I am guessing they occasionally have offcuts or the cutouts from dual bathroom sinks for example. These would only require cutting to size and edge polishing.

You could also have them drill corner holes to accept threaded lead anchors. Just size them to accept IsoAcoustics Gaia's or whatever you prefer..

@vuch I am in the exact same situation on our second floor as you are.  See my virtual system and posts.  To recap I tried spikes, no spikes, spikes on limestone slab no spikes on the slab and Herbies gliders.  The Townshend Podiums were the thing that worked.  Contact John at Townshend audio for the best pricing.  I also have heard that Stack Audio has some footers that are claimed to work but I have no experience with them.

@goose Nice system! Your rack looks similar to mine.

I love the way my rig sounds. However when you add something new is when you realize it could sound better or not. If I do anything, I’ll probably go with Magico A pods for my A3’s. I have their spikes into the carpeting now.

I noticed you have the Puritan 156 power conditioner. Is it the bottom center piece? How do you like it? What did you have before? What differences do you notice? I’m using a Transparent Powerbank 6 but I don’t think it is a true power conditioner? It seems more like a surge protector.

@vuch yes it is a Puritan 156.  Prior to that I have one of the Furman reference models.  It always had a slight hum because of the transformer.  The Puritan is quieter and according to my electronic "sniffer" is doing a better job of filtering out some line noise.  I also have the "city ground" unit installed.  There is no restricting of any of the amplifier dynamics and it is effective.  Where I live we have pretty clean power but I also want to ensure the protection aspect.  One of our audio club members is the owner / designer of Genesis speakers and he uses the Puritan when he travels at shows and he knows much more than I ever will.  The new version of the 156 has some really nice Furutech connectors but the price is way more than I would pay.

I think if you isolated your speakers rather than couple them to the floor there will be a big difference in bass clean up and you will experience a better sound stage, dynamics and placement and definition of instruments. 

I can whole heartedly recomend Townshend Isolation bars...gets you 90% of the podiums and wont break the bank. retail $1295..can be found used which I did for less.

For years I used Herbie's spikes on gliders on my VonScheikert speakers. Decided to try Gaia iso feet...very small improvement..sold them not worth it  for what I heard....some used Townshend bars popped up for sale ...tried them ...OMG...huge improvement. 

If you are set on Ganite slabs for their looks so be it...but for performance look at Townshend