Marble slab good for isolation?

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mfsoa

Marble slab good for isolation?
« on: 28 Feb 2007, 08:33 pm »
I have the chance to get a 2" thick marble slab - The kind that is used for analytical balances.

This would fit under my TT or preamp or CD player.

I was thinking that if supported by some Vibrapods etc. it would make a good isolation device.

Does anyone have experience with marble for this purpose, or good ideas for marble/pod/cone etc. sandwiches?

Thanks

-Mike

shep

Re: Marble slab good for isolation?
« Reply #1 on: 28 Feb 2007, 08:34 pm »
I think marble rings. can't hurt to try.

TheChairGuy

Re: Marble slab good for isolation?
« Reply #2 on: 28 Feb 2007, 08:41 pm »
Darker marble is older and denser (just a function of aging with stone)....white would be the worst choice, among marble choices, for instance.

I use a dark green cutting board under my TT...separated by four (shot filled) string bean cans with are then topped with (effective) squishy puds from LAT International.  My TT rests on all that. 

The marble cutting board is much better at overall isolation than the mdf fibreboard it replaced (looks nicer, too, for wifey  :)).  It may be nothing more than a function of the heavier weight, rather than any superiority of marble over composite wood, tho  :scratch:

gooberdude

Re: Marble slab good for isolation?
« Reply #3 on: 28 Feb 2007, 08:48 pm »
your floor's surface comes into play when figuring out what types of materials will work best.  Also, the size of your speakers and volume you listen to are other factors.  there's probably a host of others too.

i've never tried out marble that thick, but to my ears and from what i know its simply too hard a material & should not be used in this capacity, especially under your TT.  any vibes from your gear will hit the slab and go right back into your gear, messing with the sound.   a mass of that size may help keep floorborne vibes from going into your gear, but U might pay a hefty price in the loss of sonics to achieve this.

If you want a great material that's lying around and free, try empty LP album covers or simply a layer of normal cardboard, the corrugated stuff boxes are made out of.  just slip a few pieces under inbetween your gear and the rack's shelf.

i'm a fan of tonewood platforms, but these should really be used with footers designed to drain vibes...the mapleshade records technology.   from what i'm hearing lately, empty album covers essentially do what tonewood plats do (when no footers are used).


Daygloworange

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Re: Marble slab good for isolation?
« Reply #4 on: 28 Feb 2007, 09:00 pm »
TCG,

What are the dimensions for your platform? I have some neat stuff here (samples given to me)that I'd like to know the effects of in a TT type aplication. You TT guys might wanna check it out. I'll cut it and send it out to you.

Cheers

TheChairGuy

Re: Marble slab good for isolation?
« Reply #5 on: 28 Feb 2007, 09:23 pm »
Hey DGO,

As it happens, the top of my Target three shelf rack (where my TT atops) is 14 x 18".....a perfect fit for many, many cutting boards.  I have no earthly idea why an equipment rack (top shelf) and a cutting board would be a near exact fit for one another...but I'm kinda' glad it worked out that way :). I just measured my marble slab...it's only 1" thick. 

Whatever you'd send (not sure if you are suggesting wood or marble samples) - the freight would be the killer.  They're pretty big and quite heavy as a rule  :) 

John

jqp

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Re: Marble slab good for isolation?
« Reply #6 on: 28 Feb 2007, 09:43 pm »
I have the chance to get a 2" thick marble slab - The kind that is used for analytical balances.

This would fit under my TT or preamp or CD player.

I was thinking that if supported by some Vibrapods etc. it would make a good isolation device.

Does anyone have experience with marble for this purpose, or good ideas for marble/pod/cone etc. sandwiches?

Thanks

-Mike

Grab that slab

Marbles has a rack made of marble (unless he sold it)

richidoo

Re: Marble slab good for isolation?
« Reply #7 on: 28 Feb 2007, 11:41 pm »
High mass is not an effective vibration isolator. Freedom of motion and mechanical damping in as many axes as possible is what you want to eliminate the vibrations coming from inside and outside of the component.

Sorbothane semi-spheres, available in several sizes and hardnesses depending on the weight of the object supported, when placed flat on the supporting surface (pointing up) and properly weighted to their specified amount of "squish" will provide excellent vibration damping. There are some hifi branded sources of it, or you can just buy it from an industrial supply distributor. Wood (spruce and maple especially for music) is also an OK damping material which can be used as your shelf.

More: http://grandprixaudio.com/idx_design_wp.php

Rich

marvda1

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Re: Marble slab good for isolation?
« Reply #8 on: 28 Feb 2007, 11:55 pm »
isn't granite suppose to be much better than marble because of the crystal structure?

Daygloworange

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Re: Marble slab good for isolation?
« Reply #9 on: 28 Feb 2007, 11:56 pm »
TCG,

The stuff I'm talking about is a product called "Quash". It's by Dow Chemical. It's a sound absorbing polyethylene foam. A colleauge of mine is the distributer for it here. I have a skid of it sitting on a rack in my shop. He gave it to me to experiment with.
It's not heavy at all. Just try it and let me know what the net effect is. I have no idea how it would work under a TT. I was thinking of trying it under amplifiers, or CDP's, just for kicks.

Here's a link:  http://www.earsc.com/pdfs/engineering/literature/ProductBulletins/PB120Quash.pdf

PM me your address if you want to give it a whirl.

Cheers

brj

Re: Marble slab good for isolation?
« Reply #10 on: 1 Mar 2007, 12:16 am »
Quote from: Daygloworange
The stuff I'm talking about is a product called "Quash". It's by Dow Chemical. It's a sound absorbing polyethylene foam.

Interesting... http://www.earsc.com/pdfs/engineering/literature/ProductBulletins/PB120Quash.pdf

Wayner

Re: Marble slab good for isolation?
« Reply #11 on: 1 Mar 2007, 12:27 am »
Forget about squash. Granite is the greatest vibration stoping material on earth! don't let anyone fool you on this notion. I have 2 turntables on top of granite slabs and there is zero feed back from the base of the unit.

At my company, we build the suspensions for the reader heads for most hard disc drives in computers, we have many machines designed with granite (marbel is almost as as good) slabs to stop vibration. When you are doing mesurements down to 1 micron, you can't have stuff moving.

W

TheChairGuy

Re: Marble slab good for isolation?
« Reply #12 on: 1 Mar 2007, 04:18 am »
DOW and Ear are very impressive companies...not overpriced audiophool outfits for sure.   I'd love to try it - thanks :)

I've never been completely satisfied about marble alone...at least the 1" thick variety I have as it does makes a 'plink' sound instead of a 'thunk' or 'thud'when I tap my nails against it.  That tells (or, at least, infers) me that it's less than 100% completely effective.  The Quash stuff seems effective right where you'd want it the most with TT's...low and middle frequencies.

I assume it's soft so I'll need to put a penny under it as it then sits on 4 spiky feet in my Target rack.

You got PM coming - and thanks again.  I can PayPal you the freight if you'd like - it's gonna' add up to something just as it's going far and between two counties-  even if it is light.

Thx, John / TCG

djbnh

Re: Marble slab good for isolation?
« Reply #13 on: 1 Mar 2007, 11:07 am »
I have the chance to get a 2" thick marble slab - The kind that is used for analytical balances.

This would fit under my TT or preamp or CD player.

I was thinking that if supported by some Vibrapods etc. it would make a good isolation device.

Does anyone have experience with marble for this purpose, or good ideas for marble/pod/cone etc. sandwiches?

Thanks

-Mike
Interesting question - here's how I have my TT arranged, with a marble slab resting between two sets of cones (one set of cones rest on Q-Dampers):
.

I experience no ringing, etc. I note I use granite under other components - there's a stone business in town that has a discard pile with plenty of rectangles lying around for free, can't beat the price of free tweaks...  :wink:

denjo

Re: Marble slab good for isolation?
« Reply #14 on: 1 Mar 2007, 05:21 pm »
Nice but it looks mighty precarious - double balancing act. I have granite (bblack galaxy) as isolation platform, very heavy but I think it works!


Pez

Re: Marble slab good for isolation?
« Reply #15 on: 1 Mar 2007, 05:35 pm »
I've never used marble for a TT, but I have used marble and granite as a uniform surface for my speakers on top of my stands.  I found that with speaker stands, they have the spikes the anchor the speaker to the stand. The problem is the wood is damaged on the speaker AND the balance shifts over time.  So as a solution I experimented with a marble base and a granite base.  I found that the granite base didn't add anything to the sound where the marble made the sound slightly more "busy" I don't know how to explain it, it just sounded as if there was something added. Granite was just better. Any way it's not the same for a turntable or any other component for that matter, but that's my $0.02.

Daygloworange

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Re: Marble slab good for isolation?
« Reply #16 on: 1 Mar 2007, 06:07 pm »
I'm going to send TCG 3 pieces of "Quash" to try under his TT and other components. He'll post his thoughts about it here in this thread I'm sure.

I'm going to be using the rest of it for some well type diffusors/absorbers. I'll post about that when I get it done in the Acoustics circle.

Cheers

gooberdude

Re: Marble slab good for isolation?
« Reply #17 on: 1 Mar 2007, 07:12 pm »
here's a link to a pretty wild use of corrugated cardboard under a TT for isolation.

no idea if this a sheet of std cardboard or if the guy made it...

http://www.audioasylum.com/audio/tweaks/messages/142070.html

TheChairGuy

Re: Marble slab good for isolation?
« Reply #18 on: 1 Mar 2007, 09:25 pm »
Cool DGO - thanks  :thumb: