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Vibration Isolation for equipment using granite?

I recently visited a high-end audio salon and in the course of discussions with the owner, we discussed the large number of black granite 18x18" blocks he had against the wall. He said that he dealt with a granite retailer to make them from scrap granite pieces from kitchen installations, etc. He said that all equipment (amps, pre-amps, cd platers, DACs, streamers, turntables, etc.) all seemed to benefit from having them underfoot, even on quality equipment racks. It made me wonder if this was true or snake oil? I have my equipment (except power amp) on a Standesign equipment rack with each MDF shelf resting on small aluminum cones that "isolate" it from the steel frame. Question is, does this just add mass which would or wouldn't dissipate the vibration energy or does it work (maybe on another principal). And would sandstone or marble drink coasters, especially with cork soles) work better? Has anyone tried ay of this? Thanks in advance.

cooperdude6
o_holter
993 posts
 

Strictly off topic, but it does not harm that some granite looks beautiful as well. Here is larvikite, my rack resembles pictures C and D. 

https://www.researchgate.net/figure/Larvikite-subtypes-polished-slabs-7-x-7-cm-a-Kjerringvik-b-Bergan-c-Klastad_fig7_267806277

bimmerlover's avatar
bimmerlover
158 posts
 

Mass stores vibration [energy] and thus does NOT dampen it. 

What you want is tuned dampeners (eg springs) on a light and stiff platform (or screwed in, such as isoAcoustic Gaias on a speaker, with the proper version of the Gaias depending on the mass of the speaker).

Tuned meaning matched properly to the load. You obviously need a lot stiffer dampers for a 120 lbs speaker vs. a 50 lbs amplifier vs. a 10 lbs turntable. 

ericba's avatar
ericba
148 posts
 

I don't know if using granit with amps or TT  can improve sound but it definitely improved the sound when used under my Dynaudio Contour Legacy even if they have cast iron bottom integrated plates. The bass is tighter among others. Used 3/4 inch. Worth testing on other components.

whart's avatar
whart
3,372 posts
 

Constrained layer is the way to go; I use an HRS platform on a big Minus K isolation platform for a very heavy high mass table (Kuzma XL plus Airline arm). 

I'm not sure one stone over another is the answer.  You can probably make what is necessary if you know what you are doing- I went for commercially available solutions -- works a charm. 

bdp24's avatar
bdp24
10,487 posts
 

 

@cooperdude6: Lots of great comments here, and a link by @ditusa to an excellent article. Here are my thoughts on the subject:

 

- First, replace the aluminum cones with springs. Cones do NOT isolate, they couple. Sets of four springs from Douk Audio are cheap.

- As many have already said, constrained layer damping works great. But first you want to at least get rid of the MDF shelves, which suck. MDF is nothing more than wood pulp mixed with glue, not at all stiff. I put a 50lb. turntable on the top shelf of my Solid Steel rack, the MDF resting on four corner cones. The MDF remained supported at only the corners, the shelf bending all the way down to the rack’s metal frame in between.

- Replace the MDF shelves with pieces of Baltic Birch plywood. 3/4" thick, 19 layers of cross-laminated Birch. VERY stiff for a wood product. A layer of Baltic Birch plywood with a second of another dissimilar stiff material (sure, granite if you wish) and a sheet of a constrained layer material (check out WallDamp from Acoustic Sciences Corporation) between them makes a great shelf. And at a relatively reasonable price.

 

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