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Sorbathane under granite slabs for speaker bases?

I’m getting two 12"x12" granite slabs to use as bases under my KEF Reference Model 2s via spikes. They will be sitting on a 5" high hollow tile shelf. Would using thin (.25") 70 duro sorbathane under the slabs help in isolating the speakers or will it possibly negatively impact the sound?

Thanks for any input.
asahitoro
mains
170 posts
 
for a cheaper option you can use your granite , but use the seismic cells underneath , you will just need to work out the weight of the loudspeaker adding on the weight of the granite , then you have basically made your own version of the podiums at a bargain price 
the seismic load cells (pods) can be made to isolate any weight , i would recommend a set of 4 under each granite platform , do not use your spikes ,just place your speakers straight on top of the granite or you can use squidgy pads to dampen any ringing between the granite and the base of your speakers good luck 
geoffkait's avatar
geoffkait
23,365 posts
 
When granite is used with springs you get the benefit of high mass and low resonant frequency - below 3 Hz if you play your cards right. As a bonus there are no resonance issues with granite since it's isolated along with the component, thus no reason to apply damping, always a plus in these delicate matters. The inexpensive way to play with the big boys. Certainly no reason to spend a fortune. The only issue for springs is center of gravity, I.e., tall heavy speakers might be too top-heavy to place springs directly under them. But there is more than one way to skin a cat. Subwoofers are ideal since they have low COG.

geoff kait
machina dynamica
isolation & resonance control
bdp24's avatar
bdp24
9,736 posts
 
The Townshend Seismic isloators are also available separately, as individual "Pods". Using three or four of them under a speaker (or any other component) provides isolation to a very low frequency, and is cheaper than the Seismic Shelves themselves, which are not really required---the Pods are doing all the isolating, not the shelf.
bdp24's avatar
bdp24
9,736 posts
 

I should have mentioned that the Townshend Seismic Isolators are also offered on a number of different "platforms". In addition to the individual Pod which can be used in sets of three or four for use directly under a component, Townshend makes the Seismic Platform, which is a thin shelf with a Pod bolted onto each corner, onto which a component may be placed. There is the Seismic Podium, which is similar but for a speaker enclosure to be placed upon. Then there is the Seismic Bar, a pair of outriggers for a single speaker with a Pod bolted onto each end. That is good for the narrow/deep proportioned speaker enclosures, the outriggers giving the enclosure a wider, more stable footprint. Also available is the Seismic Corner, which has a pair of Seismic Pods bolted onto a metal bar that is placed under the corner of an equipment rack, four Seismic Corners obviously required (with a total of eight Pods). And then the Seismic Rack, which has a pair of Pods under each corner of a four-shelf rack, each shelf being a Seismic Platform.

Each individual pod comes in seven weight-appropriate versions, from 2lbs. to 140 lbs.

ebm
9,311 posts
 
For the best sound look at Symposium Super Plus with spikes for cement floors or without for all wood floors, Granite rings and is tipped up for thin highs,Good luck though.
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