Best surface, Marble, slate, cutting board???

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cats squirrel
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Re: Best surface, Marble, slate, cutting board???

Post by cats squirrel » 18 Nov 2019 16:30

Marble, slate or cutting board? Well, distilling everyone's thoughts, any of them, and none of them. Goatbreath got off to a good start.

A large mass of material on which to place the other bits of the construction will work, if suitably supported, ie it is rigid and will not move. This he calls his 'Mass Barrier'. This works, not because of the mass, per se, but because of its very high mechanical impedance, which is proportional to density, thickness and flexural rigidity. Then, if you place rubber/sorbothane feet onto this, which have very low mechanical impedance, transfer of energy (in either direction) will be very low. Now place a thin (up to 10mm) of a suitable material on top of the feet, and you have an effective sound barrier. However, the 10mm of suitable material must have a high damping factor, and to do its work efficiently, have the same mechanical impedance as the turntable so that vibrations can be transferred to the damping material, where it will be damped. The TT itself must be damped, too.

However, goatbreath's ideas about suitable damping materials is not correct. Spruce**, which is used for sound boards for guitars (and other stringed instruments) is not suitable because it has very little damping. Mdf won't work for the same reason. In fact any material which has a low damping factor is useless in that position. However, a resinated bamboo chopping board would be quite good.

**Spruce, in particular Sitka spruce, is used by Luthiers for sound boards, because it does not damp the sound being radiated. But they prefer the grain to be very close together (very slow growing) rather than fast growing. Spruce (pine in general) tends to prefer less warm climes, anyway. HTH

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Re: Best surface, Marble, slate, cutting board???

Post by Brewman2 » 18 Nov 2019 17:53

http://www.kansoaudiofurniture.com/p6.html

I don't even know the price of this stuff but it's probably beyond my wallet. The wall shelf looks amazing. Interesting thing is they are not using stranded wire to suspend that shelf. These guys seem to know physics.
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Re: Best surface, Marble, slate, cutting board???

Post by wack99 » 19 Nov 2019 04:33

ikea chopping board on squash balls worked great for my P6, also remove the lid to help with vibrations.
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goatbreath
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Re: Best surface, Marble, slate, cutting board???

Post by goatbreath » 19 Nov 2019 06:01

cats squirrel wrote:
18 Nov 2019 16:30
Marble, slate or cutting board? Well, distilling everyone's thoughts, any of them, and none of them. Goatbreath got off to a good start.

A large mass of material on which to place the other bits of the construction will work, if suitably supported, ie it is rigid and will not move. This he calls his 'Mass Barrier'. This works, not because of the mass, per se, but because of its very high mechanical impedance, which is proportional to density, thickness and flexural rigidity. Then, if you place rubber/sorbothane feet onto this, which have very low mechanical impedance, transfer of energy (in either direction) will be very low. Now place a thin (up to 10mm) of a suitable material on top of the feet, and you have an effective sound barrier. However, the 10mm of suitable material must have a high damping factor, and to do its work efficiently, have the same mechanical impedance as the turntable so that vibrations can be transferred to the damping material, where it will be damped. The TT itself must be damped, too.

However, goatbreath's ideas about suitable damping materials is not correct. Spruce**, which is used for sound boards for guitars (and other stringed instruments) is not suitable because it has very little damping. Mdf won't work for the same reason. In fact any material which has a low damping factor is useless in that position. However, a resinated bamboo chopping board would be quite good.

**Spruce, in particular Sitka spruce, is used by Luthiers for sound boards, because it does not damp the sound being radiated. But they prefer the grain to be very close together (very slow growing) rather than fast growing. Spruce (pine in general) tends to prefer less warm climes, anyway. HTH
OK so would Contiboard/Veneered Chipboard have a high damping factor because the chipboard is made of random particles and glued,so the vibration would not be able to travel down the grain like with Spruce..?? Chipboard is also less dense than MDF.. I was thinking the vibration would travel out of the Spruce quickly,so not be stored..I know you have built and explored plinths,so I bow to your superior knowledge here.. :)

How about this,I Imagine the other side is Flat..
https://www.ikea.com/gb/en/p/laemplig-c ... -00394380/

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Re: Best surface, Marble, slate, cutting board???

Post by AsOriginallyRecorded » 19 Nov 2019 07:06

I believe cats squirrel to have the correct thinking here. Some abstract thinking here, but imagine one of those executive toys with the swinging steel balls. Picture vibrations travelling in a similar fashion, with the vibration dissipating over distance through the same material. Slip something of a different density and particle alignment between the balls, and much of the vibration disappears. A similar approach with stereo components, particularly turntables will have similar results. Extrapolate this "image" to the materials available to build a cabinet, shelf or even a big old desk to hold your TT. Every case will be unique to some extent.....so, YMMV.
That hanging gardens of stereo equipment looks pretty clean and futuristic, and expensive. Two main considerations in wall shelves is identifying the inertness of the wall itself to vibrations, and in some cases, the ease of access to components. Oh, and for some of us, a third consideration...does it pass the inspection of your significant other? :lol:

cats squirrel
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Re: Best surface, Marble, slate, cutting board???

Post by cats squirrel » 19 Nov 2019 20:18

goatbreath wrote:
19 Nov 2019 06:01

OK so would Contiboard/Veneered Chipboard have a high damping factor because the chipboard is made of random particles and glued,so the vibration would not be able to travel down the grain like with Spruce..?? Chipboard is also less dense than MDF.. I was thinking the vibration would travel out of the Spruce quickly,so not be stored..I know you have built and explored plinths,so I bow to your superior knowledge here.. :)

How about this,I Imagine the other side is Flat..
https://www.ikea.com/gb/en/p/laemplig-c ... -00394380/
chipboard on its own is quite good (I measured a damping factor of 0.228, anything about 0.2 or above is good, but there are several kinds of chipboard!) but melamine faced chipboard may not be quite as good, as it is less flexible. I think chipboard (particle board in the US) works well because of the friction generated between the chips of wood, causing low grade heat, and dissipating the vibrational energy.

Vibrations in panels (called plates in physics) do so in a very precise manor. It is the whole plate that moves, not small parts of it. In thin plates, the only movement is up and down, thick plates also have shear to deal with, which move sideways. Add to that the complication of wood being anisotropic (it behaves differently in each direction) and things get complicated.

Look at this pic of a laser beam interferometric hologram of a guitar sound board.

https://www.acousticguitarforum.com/for ... ?p=6175445

It shows (the light and dark concentric circles) where the sound board of a guitar moves, depending on vibrational frequency. The concentric circles are the in and out phases, but any one set of circles represent the whole area is moving either up or down. Look at the bottom pic, the fourth one. Virtually the whole surface is moving (as one), and is the fundamental resonance frequency. Now look at the one second from bottom, there are two regions moving, one will move up while the other moves down, the swap according to the frequency. It is the second harmonic. You can also see that things can get pretty complicated, pretty soon.

The Ikea 'LÄMPLIG' is quite good, I measured the boards to have a damping factor of 0.2, just good enough. BUT some of those boards are hollow, so beware. LÄMPLIG is fine, though, I have two.

HTH

cats squirrel
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Re: Best surface, Marble, slate, cutting board???

Post by cats squirrel » 19 Nov 2019 20:25

AsOriginallyRecorded wrote:
19 Nov 2019 07:06
I believe cats squirrel to have the correct thinking here. Some abstract thinking here, but imagine one of those executive toys with the swinging steel balls. Picture vibrations travelling in a similar fashion, with the vibration dissipating over distance through the same material. Slip something of a different density and particle alignment between the balls, and much of the vibration disappears. A similar approach with stereo components, particularly turntables will have similar results. Extrapolate this "image" to the materials available to build a cabinet, shelf or even a big old desk to hold your TT. Every case will be unique to some extent.....so, YMMV.
That hanging gardens of stereo equipment looks pretty clean and futuristic, and expensive. Two main considerations in wall shelves is identifying the inertness of the wall itself to vibrations, and in some cases, the ease of access to components. Oh, and for some of us, a third consideration...does it pass the inspection of your significant other? :lol:
It's not my thinking, it's how the physics works. But what you have written is about mechanical impedance, vibrations don't 'travel' as you have put it. Density is relevant, but particle alignment is lost on me! Of course, the energy does not disappear, it is converted into heat. In every case, the problems will be the same, as virtually any structure can be broken down into plates, beams and shells, all of which have been analysed for vibrations, and how they interact.

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Re: Best surface, Marble, slate, cutting board???

Post by AudioFeline » 20 Nov 2019 10:13

From what I have read on plinth building, hardwood ply is better than chipboard - the grain runs in different directions and is able to dissipate the energy. Mdf and softwood ply is not highly regarded for a heavy plinth.

cats squirrel
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Re: Best surface, Marble, slate, cutting board???

Post by cats squirrel » 20 Nov 2019 13:19

A 'heavy' plinth isn't recommended in any material. A heavy plinth becomes the immovable object, so no damping can take place, so any turntable connected to it must damp the vibrations itself. How many can?

Plywood has very little damping, (I measured 0.04, compared with chipboard of 0.228, and mdf 0.017). The problem with chipboard is the finish, but it can be veneered to very good effect. I have two original teak veneered chipboard plinths, and they are very good. But they are frame type construction, not the 'stick lots of layers together and pray' type.

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Re: Best surface, Marble, slate, cutting board???

Post by goatbreath » 20 Nov 2019 14:33

I take it glass as a material is not good.. ??

That includes for Amps and CD players too..

cats squirrel
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Re: Best surface, Marble, slate, cutting board???

Post by cats squirrel » 20 Nov 2019 17:52

glass has very little damping, unless it's laminated.

Look here: https://www.tapatalk.com/groups/audioqu ... s-t29.html

It will give you an idea of what's good, and what's not. :wink:

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Re: Best surface, Marble, slate, cutting board???

Post by Brewman2 » 30 Nov 2019 01:54

Thanks for so much good input! One of the post said look for something around the house... well I finally remembered that I did have a slab of marble. Turns out I had a marble chess set , that has been put away for years. So... I'm using it. I was first using a plastic audio video stand. I acquired a metal video stand /cabinet. With all the weight on it it's very sturdy and non- resonant. Now I don't hear that excessive Rumble between songs. I've made a new place for vinyl playback in my studio. Which wasn't easy, I had a lot of rewiring to move things to accommodate it. As I've just gotten back into listen to the wonderful output of vinyl. I've been digitally lost for so many years! I totally forgot about just sitting back and listening to music.
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Re: Best surface, Marble, slate, cutting board???

Post by AsOriginallyRecorded » 30 Nov 2019 05:04

well, with all due respect, I suggest that you are incorrect, regarding travel and vibration, as any simple googling of "do vibrations travel" will yield a long list of articles on the topic. Particle alignment....each material has a consistent typical arrangement of the atoms, molecules and building block units of it's elements. This alignment determines much of the physical characteristics of the material under specified conditions. Vibration traveling....repeat, traveling through various substances is alternately attenuated by the alignment of particles and molecular shapes in the material. This is why alternating materials will reduce the vibration from one material to the other, such as when using an isolating pad between a turntable, for instance, and a dense solid like a concrete slab or wood fibre cutting board. Assuming a reasonably sprung TT, various material selections will produce varying effective results. The principles are easily understood and comprehended, the methods to attenuate are less clear. Hence, YMMV. For what it is worth, I have had good success with using thick slabs of fine grain cedar, a relatively light and fine grain (high density) wood for speaker risers, with a carpet isolator between block and speaker. Likewise, the close cell foam mats have proved very successful. We are not all blessed with extensive degrees in physical sciences, but using relatively simple models does help clarify what we are dealing with, and some alternative methods of dealing with it. :)

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Re: Best surface, Marble, slate, cutting board???

Post by AudioFeline » 30 Nov 2019 07:28

Good to hear the marble chess board has solved your problem. Would the b+w chessboard pattern show if it was turned it upside-down?

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Re: Best surface, Marble, slate, cutting board???

Post by kalaur » 01 Dec 2019 02:35

cats squirrel wrote:
20 Nov 2019 13:19
A 'heavy' plinth isn't recommended in any material.
I suspect every mass loaded turntable manufacturer would argue this.

cats squirrel wrote:
20 Nov 2019 13:19
A heavy plinth becomes the immovable object, so no damping can take place, so any turntable connected to it must damp the vibrations itself. How many can?
Go rap your knuckle on a cinder block while touching it with your other hand. Now rap your knuckle on a cardboard box while touching it with your other hand. Cinder block is certainly heavier than the cardboard, yet it transmitted no vibrations to your hand. Plinths are not there to just damp vibrations. If they don't vibrate in the first place from external forces (footfalls, trucks driving by, bass, etc), that's step one.