Granite or Marble?

SDA1C

For the plinth/stand. Granite or marble?

Clearly they look close enough to one another to not dwell on visual....is there an acoustical difference

Toolfan66

I thought granite was known to have a ring to it??

SDA1C

Not sure. That's why I ask. They want $200 for the granite fab. Better suggestion?

Looks like Mapleshade wants 250 but I don't like the color. I want ebony.

janmike

Thick slate is also an option. When polished, it will look nice as well.

Joe08867

I have used both and have an opinion but it depends on the use.

For a Turntable Marble, Glass or Acrylic. For an Amplifier Granite. For Tubes Hardwood. For Speakers Granite, Slate or Concrete.

drumminman

TOOLFORLIFEFAN wrote: »

I thought granite was known to have a ring to it??

I've also read this, but I've never tried a piece of either. What about a thick piece of Maple? It's a tone wood that many have used to good effect under amps, CD players, pre-amps, etc.

Joe08867

I prefer wood for Tubes to help limit harmonics. I have tried the same Tube amp on Granite, Marble and Heavy Dry Maple and the Maple was able to eliminate the Harmonics I would get from time to time. I would surmise that the same would hold true for CD Players and Tape Decks but have found that turntables prefer harder items like Thick Glass or Acrylic.

dorokusai

Either would be fine.

Jstas

I guess it matters more about looks when stone is concerned. But if vibration dampening is what you want, mass is your friend. Higher mass takes more energy to move so it doesn't transfer energy as easily. So which ever stone is more dense, that's what I would go with.

Granite is hard but hard does not equal dense. Hard just means the crystalline structure is stronger. Marble is a metamorphic rock. It's essentially a sedimentary or carbonate based rock that was heated and squeezed to change it to a marble. It ends up being very dense although it can be very soft and porous. Granite is an igneous rock formed from crystals of various types compressed together. Granite is very hard but not as dense as marble. I would imagine that because of granite's lack of an internal structure and mismash of various types of crystals, it would have a propensity to have a "ring" to it.

This is marble under a microscope:



It's a mishmash of crystals as well but they are relatively uniform in size and the largest crystals are isolated in a sea of smaller ones.

This is granite under a microscope:



Notice how the large crystals are actually touching each other and are surrounded by smaller crystals that just seem to fill in the gaps. There also seems to be some voids in the rock as well. Those large crystals touching each other transfer energy pretty easily and that's likely why granite "rings".

The average density of granite is between 2.65 and 2.75 g/cm3

The average density of marble starts at 2.76 g/cm3 The average is 2.81 g/cm3 +/-.5 g/cm3

That's grams per cubic centimeter.

I know it doesn't seem like a big difference but .2 grams per cubic centimeter is significant. Just look at the differences in the pictures I posted. So given all that, I'd go with marble for a plinth in a turntable.

EndersShadow

Jstas, that is by far the best post I have seen this week.

I have been debating granite plinths for my LSi 15's but this has me rethinking that idea.......

Great information!!!

SDA1C

Spikes on my 1c's are not going to happen. (I will neither drill holes or remove the base ring) Will a marble plinth make as much difference as the spikes are said to make? I love the info jstas I can't thank you enough. As with most other hobbyist ideas it has got me thinking in a million other directions now as well.

EndersShadow

Why not spike the plinth? Two birds one stone

SDA1C

We were just discussing that. To be honest...I have no reason not to. Neither does she lol!

F1nut

SDA1C wrote: »

Spikes on my 1c's are not going to happen. (I will neither drill holes or remove the base ring)

Why not? Polk did with the higher end models, it's no biggie. You don't drill all the way thru the base, just enough to mount the threaded insert. Another option since you have the Studio version, glue a block of wood into each corner of the base, then add the spikes to the blocks. I almost did that to a set of Studio 2B's, but didn't like spikes set in so far, so I removed the base trim and added 2" tall spikes to the cabinet close to the corners. Polk used long screws to attach the base, which go into the cabniet, so I had to fill the holes. Again, no biggie.

Will a marble plinth make as much difference as the spikes are said to make?

No.

SDA1C

I don't know....Maybe I should consider it. I just have this allergy to holes in my speakers. I will say they would look awesome with spikes instead of the base ring. I'm on the verge of a fairly decent up grade in a lot of different areas. Maybe spikes will get tossed in too?

1C

MillerLiteScott

I found Maple to sound better than any stone under my speakers and also found that through bolted spikes through the bottom of the cabinet resulted in better tighter bass clarity. YMMV

SDA1C

FINE! So I now have spikes for my 1c and 11t. Hehe. Getting anxious!

dpowell

I used granite for my 1C's with great results in the bass dept. I don't need them now that I have the 2.3's with their own spikes. I can ship the granite to anyone at their expense.

SDA1C

dpowell wrote: »

I used granite for my 1C's with great results in the bass dept. I don't need them now that I have the 2.3's with their own spikes. I can ship the granite to anyone at their expense.

I might consider that. What on earth does it weigh? lol What color are they?

Thanks, 1C

decal

scumbag spammer reported

BlueFox

Maple. Stone reflects sound and adds to distortion.


http://shop.mapleshadestore.com/departments.asp?dept=46

Moose68Bash

Jstas,

Thank you for that great explanation.

I live in the "Granite State" and have been considering setting my 1Cs (with spikes installed as suggested in this thread) on granite blocks (about 3" thick) where they are located in my basement. The purpose of the blocks is both to give them a very stable foundation and to elevate them off the floor because we occasionally get about 1" of water in the basement during spring "mud time."

With the 1Cs on spikes on granite blocks, do you think marble vs. granite blocks would make a difference?

tonyb

Marble or granite won't make a spit of difference which one you use under gear/speakers. You not eating on the stuff, spilling wine on it either, so don't worry. Use which ever is eye catching to you.

cnh

When I do run my SDAs, I have to run them in the basement (no other room is large enough for "correct" placement). The basement has a solid floor of "concrete" well over a foot in depth, the finished room is covered by a late '70s indoor/outdoor nylon carpet (an ugly orange pattern) that has a 1/4" rubber matting or less glued to it. You can pretty much feel how "hard" the floor is in your stocking feet. It's like having your speakers on several TONS of a concrete slab that's about 20' x 10' in the room and continues throughout the unfinished part of the basement. I doubt the speakers are doing anything to that slab! lol

Got SDA's, got concrete, you're good!

cnh

mhardy6647

Slate or soapstone.

halo71

Nobody else notice that the reported spammer necro'd this old thread?:cheesygrin:

But, while on the subject. I guess I am lucky to live where I do. Near a major granite minning/cutting town....Elberton, GA. And I have a friend that just gave me 2 2" thick slabs of Dakota Mahogany granite free. I asked him to cut the length and width I wanted, I plan to put my Infinity RSIIIa's on them. I can get more, but shipping would be outrageous! Any Georgia/South Carolina Polkies interested PM me. Free of course.

72RR

The purpose of the blocks is both to give them a very stable foundation and to elevate them off the floor because we occasionally get about 1" of water in the basement during spring "mud time."

First, I think I'd worry more about eliminating the water than anything else.

Moose68Bash

72RR wrote: »

First, I think I'd worry more about eliminating the water than anything else.

That would require somehow defeating Mother Nature or circumventing the laws of physics! Hydrological pressure when the ground surrounding our house is super-saturated in the spring on occasion forces water up between the foundation and the basement slab. But, the water does not cover the basement floor, and it has never exceeded an inch in depth even in the spots where it "puddles."

Yesterday, I purchased two 2" x 12" x 18" granite pavers to use to set my SDA 1Cs on. They are, in fact, in a spot where the basement floor has never been wet -- and, I hope, never will be.