Topic: Stone suitable for plinths?

[Jimna]

any reason why any rock is better than the other?  i have a reasonable supply of flagstone and other ornamental rock available at a resonable price.  i know the fav is marble & granite but is that just because its pretty or is there an actualy acoustic reason?  ive also seen highend studios using concrete which brought me to this question.

[Gutbucket]

I'm also curious for some floor standing speaker plinths I'm planning to build.  I assume a dense material is what is most important for maximizing mass, but I'm sure you can dig up plenty of resonance issues that tweako-weirdo-philes would love to get all 'riled up over.

I was thinking of either casting some concrete slabs, or using some locally quarried limestone with nice looking ancient shells and petrified sea creatures in it.

[Jimna]

you answered my question with a question.

just sayin'

[mfrench]

slate
slate
slate

here is a fairly intensive discussion on slate:
http://www.lencoheaven.net/forum/index.php?topic=1471.0

[Gutbucket]

It appears that slate would be a good choice, Jim. 

[mfrench]

that thread goes into a sidebar about the coral limestone from your area. That one seems like a good choice as well, but perhaps a bit weaker structurally.
At any rate, there was also quite a bit of discussion about laminating slate and coral stone as being a quality marriage of materials.

I like flagstone, as long as its not the dust creating arizona sandstone flagstone. i'd like to think about a flagstone called Three Rivers or Sawtooth (presumably from the idaho/montana border area).
Its similar to sandstone flagstone, but without the sloughing property.

[Chilly Brioschi]

Steal some "coquina" from Castillo de San Marcos in Saint Augustine, FL.

Coquina is a sort of cement made from very old seashells.
It seems to look like lumpy plaster and is "dead" sonically as best as I can tell.
It weathers like cement, maybe better.

Strange, strange stuff
Probably could make it in a burr-grinder with some seashells           

[Jimna]

im focusing on this tomorrow.  ill keep the sandstone element in mind.

[Jimna]

anyone familiar with cutting flagstone?  or any rock for that matter?  found it cheap by the lb, but its uncut.

[mfrench]

A dry diamond blade will work, as will abrasive blades; both mounted to a circular saw.
The dry diamond blade is way more efficient - the abrasive blades are way more affordable.

How clean do you need the cut to be?
Most of the time, a mason will score a cut line with a saw, and then snap the stone over a hard sharp edge - a 2x4 will work; you just need something to fracture the cut line over.
They'll then come back with a chisel and "hand-hew" the edges giving it a chiseled look rather than a sawed off look.

what are you 'plinthing'?

[Jimna]

what are you 'plinthing'?

speakers.  just bought some rinsed concrete slabs for the bases.  ill put some sort of dampening between them and then cover them so you dont see concrete.  still need a 2-4" thick top piece that will look pretty like flagstone, marble, granite, ect.. 

[mfrench]

that'll be nice.
Another option is a pro cutting. The silica dust that you'll raise with a dry diamond blade is anything but healthy. If you do go dry, make sure that you're well protected and ventilated.
A local stoneyard near me does cutting of slabs with a large wet wheel. I'd bet you could find that sort of service locally for not too much.

[Chilly Brioschi]

Have you folks seen this stuff?
It might be interesting in a laminate with other materials:

http://www.quietsolution.com/html/quietrock.html

[Jimna]

so i built a set of plinths for the speakers finally.  i moved the couch and chair all behind my desk so the love seat is slightly forward but the only thing in the speaker side of the room.  i also got the old speaker cabs out and with all that air space opened the image and general sound of the room changed allot.  it sounds bigger with a more pronounce sound stage.  also adding the plinths gave the bottom end a rinse, cleaning i up a bit while giving the whole presentation over-all a quickness.  dropping the height also helped a bunch as did the move away from my front wall.   i plan to make wood sides on the concrete bases that has a stain that matches the speakers possibly this weekend.   







ive already got plans to built a rack for my electronics anyway.  why not make things to match...

[Gutbucket]

Clean. The bottom one looks like the glossy hifi magazine ad shot. Strong work & good thickness on the stone.  Anything between the slab & blocks?

Consider the same materials for the rack- longer, thinner slabs for shelves and the same wood as risers.. or the other way around.