The Good Turntable

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Cats,
Again I agree with you in your observations. But when you discuss composites that is a wide open description. Being from the plastics and aerospace side of things there are so many different materials and combinations that it is hard to make any blanket statements about those materials. Carbon fiber composites will have very different properties, including damping over fiberglass based composites. I have seen some carbon/epoxy composites that would ring just like a bell and have very poor damping in fact. So not only do you have to look at the fiber, but fiber combinations and also resin types. I am sure that what you are looking for could be done but would take some serious testing and experimentation to create the composite properties that you would be after.
 
Cats,
Again I agree with you in your observations. But when you discuss composites that is a wide open description. Being from the plastics and aerospace side of things there are so many different materials and combinations that it is hard to make any blanket statements about those materials. Carbon fiber composites will have very different properties, including damping over fiberglass based composites. I have seen some carbon/epoxy composites that would ring just like a bell and have very poor damping in fact. So not only do you have to look at the fiber, but fiber combinations and also resin types. I am sure that what you are looking for could be done but would take some serious testing and experimentation to create the composite properties that you would be after.

yes, I would agree with you, entirely. I tested a sample of carbon fibre, and it gave a very low damping factor. But it was very stiff, and rang like metal when dropped onto a hard floor.

However, and I think this is what you alluding to, it would make very good facings in a sandwich composite. Composites is a huge subject, as you say, and where I think the future in plinth material lies.🙂
 
Yes,
Put a visco-elastic layer between two layers of carbon/epoxy and you would have a completely different animal. There is a lot of opportunity to create an engineered solution to the plinth situation if you know all the parameters that you require in the end product.
 
That is dense Plywood, made for concrete casting and often used as bottom plates in trailers...
Now we're on the subject I find shape and size more important than the material. Size and shape defines the tone and pitch of the design.
Damping is in my book bad.. what does it do..?? It damps the very energy that is supposed to create music.
 
Joachim You tell me what shape sounds good.. 🙂
I showed you a simple way to listen for pitch and tone. If something is shifted in the perception of sound through a material, then that shift will also be present in the final design. No matter what the material is. If you listen to your PC board before you listen to the circuit, you recognise the sound once you get it fired up. Aerolam is very stiff I have tested and rejected it. Sometimes to evaluate a material I make a simple shelf of it, put it on a set of cones and then place the DUT under my CD-player. Then you quickly get a grip on different things. dead sandwiched things sounds just like that. some sound thin and brittle while others have size tone and impact. those are the materials you want.

Brian did you get my Email..??
 
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something in music ties us together rhythm pace tone and color. I believe that what I like is common for most, my experience is that we very very rarely disagree when something is good. we smile when we're hit, and I guess we all have experienced the dreadful disappointment of a dull over engineered sonically dead HighEnd H-iFi product. Materials size and shapes that breathe life is for me the obvious way to go. One good example of a beautiful and really well sounding turntable is the Simon Yorke with the light citrus-tree platter.
 
That is dense Plywood, made for concrete casting and often used as bottom plates in trailers...
Now we're on the subject I find shape and size more important than the material. Size and shape defines the tone and pitch of the design.
Damping is in my book bad.. what does it do..?? It damps the very energy that is supposed to create music.

yes, size and shape do dictate the resonance frequencies of the panel, but along with some of the material's properties, which are Young's modulus, Poisson ratio, density and damping factor. The latter term dictates some of the losses and the amplitudes of the resonant peaks. The damping helps reduce the amplitudes of the vibrations which find their way into the plinth, from the turntable, from the support and from the air. A plinth without enough damping will sound coloured and confused, as sound lingers longer than it should.

So damping is essential if a clear, uncoloured sound is wanted. It doesn't suck the life out of the music, as some claim, but those people need 'enhancement' to gain pleasure from their turntable, so it would seem.
 
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