The data is one dimensional in that if you bolt or glue anything in contact with the sample then everything changes and the game starts over
The samples are about the size of an arm board and not of plinth size BTW
It would be more interesting and useful to attach the same data measurement to the complete TT package since it made reference to TT materials
Thats what is important and not just one narrow test that will never really amount to anything since no one material stands by itself by the end user, only product brochures seem to benefit
One would think the Mags would at least use this kind of testing along with listening to narrow it all down....
Regards
David
The samples are about the size of an arm board and not of plinth size BTW
It would be more interesting and useful to attach the same data measurement to the complete TT package since it made reference to TT materials
Thats what is important and not just one narrow test that will never really amount to anything since no one material stands by itself by the end user, only product brochures seem to benefit
One would think the Mags would at least use this kind of testing along with listening to narrow it all down....
Regards
David
Are you suggesting that slate is without beneficial sonic qualities -other than being more easily worked - than other heavy minerals such as granite or marble etc. for use as a plinth material? [I had intended mounting just the motor and platter unit of a Technics SP-10 a la Osmond Mills etc. and ditto for an old Lenco, both with cast iron sinks braced to the bottom of the main bearing...however any advice, even if to the contrary, would be appreciated].
He means the physical samples from the link in a post on the previous page.
damping factor values : damping factor values
A rather pointless way of measuring some values for a given material sample. As pointed out it tells you nothing about the sound of the parts as part of a 'construction'.
damping factor values : damping factor values
A rather pointless way of measuring some values for a given material sample. As pointed out it tells you nothing about the sound of the parts as part of a 'construction'.
I would think that one of the major problems with any organic material such as granite, slate or marble is that no two samples would be identical and therefor how do you qualify the material. I have seen granite used in certain situations where it was rather damped and in other situation where it would ring like a bell. It would have much to do with how the material is constrained. Another question I would have in any use such as a platter would be the imbalance of a material such as slate that can have variations in density throughout. How would you balance such a material?
Well, in essence, yes.
But, I wouldn't say it is entirely without beneficial qualities, just that those qualities are available elsewhere and probably to a greater extent.
About a decade ago, I put together a turntable using parts from Scheu. They sold me the bearing, a 50mm acrylic platter, and the motor. I built the motor housing and had a slate plinth built out of 3/4" slate which I sandwiched with 3/4" MDF. Slate is commonly used for kitchen counter-tops and a local kitchen contractor was able to build the plinth for me. I used silicone adhesive to hold the slate/mdf together. I also built a plinth out of granite and found that slate was considerably better than granite. The slate was relatively inert even before being bonded to the mdf and the slate/mdf combination is pleasingly damped. Granite, on the other hand, rang like a bell, and even after being bonded to mdf didn't sound as good as the granite. So at least in my experiment, I found slate to be a good option. Rather than spending a lot on very thick slate, I've had good success with slate/wood combinations. The wood is hidden by a 3/4" slate lip around the edge of the plinth.
---Gary
Attachments
Good eye, Joachim. Yes, it's an Immedia RPM tonearm - a predecessor to what you use on your Spiral Groove. It's a very nice tonearm which I fortunately got back in the day before prices for good tonearms exploded.
---Gary
If it wasn't clear from the rest of the message, this should have said:
Granite, on the other hand, rang like a bell, and even after being bonded to mdf didn't sound as good as the slate.
---Gary
I can't draw that conclusion from my work since I never tried slate alone. I was worried that 3/4" slate was too thin and I went straight to the slate/mdf composite. I never listened to the 3/4" slate on its own.
I can definitely say that granite alone is a bad idea.
And I've heard thicker slate plinths which I thought sounded good but they were not systems that I knew well, so it's hard to draw any conclusion.
---Gary
I have had a few SP-10 TTs over the past 20years, and they have come in several plinth styles/materials. Without a doubt the best was Technics own solid mineral 17Kg plinth, (but the 'constrained' version, obsidian + rosewood) was a comparative failure...muddy, unfocused sound. The worst one was in a 2.5" granite plinth....hard, brittle sound with little sustain. The major practical problem with the Technics mineral (obsidian) plinths was that they were very brittle and easily damaged....especially so at the mounting points. [I seem to remember that obsidian is a reformed volcanic lava-particle material.]
I think that my best approach now will be to bolt the motor to a 1.5" slate board with more lossy materials forming a sandwich around the slate top and bottom surfaces. An American maker uses a multi sandwich of slate and thin duralium sheet; this is said to be the best solution, whereas another American maker uses Panzerholst along with a cast iron vibration sink/drain to the main bearing.
However I suspect that none of this is adequately 'on-topic' as the thread concerns totally different basic design concepts than are found in my TTs. ....... so I will keep quite from now on!!
I think that my best approach now will be to bolt the motor to a 1.5" slate board with more lossy materials forming a sandwich around the slate top and bottom surfaces. An American maker uses a multi sandwich of slate and thin duralium sheet; this is said to be the best solution, whereas another American maker uses Panzerholst along with a cast iron vibration sink/drain to the main bearing.
However I suspect that none of this is adequately 'on-topic' as the thread concerns totally different basic design concepts than are found in my TTs. ....... so I will keep quite from now on!!
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Sorry for this OT. As I'm about to build the plinth, this is of high interest to me. Also, I've seen Joachim refering to Panzer on the OB thread, so seemed semi relevant. So for pushing this OT to the end a little note that Clearaudio have used Panzer for their tables, sandwiched between aluminum.
Ovation: Clearaudio Panzerholz
Innovation: Plinths
Ovation: Clearaudio Panzerholz
Innovation: Plinths
seems to be a lot of confusion in the discussion, here. The tests are very relevant to audio design work, as evidenced by many people and some companies.
The three major parameters that predict the outcome of plinth material choice is stiffness, mass and damping factor. If you haven't comes to terms with these, choosing materials is really hit and miss (mostly miss).
Materials that have very little intrinsic damping are not going to be useful (except to look at) for audio work where damping vibrations are necessary, whether for turntables, loudspeakers or shelves.
So testing materials, even small ones, as long as the dimensions are within the ASTM or ENV guidelines, are very useful (and indispensable) to choosing suitable materials.
Of course, one could choose materials by how they look, then try to convince yourself you made the right choice.
The three major parameters that predict the outcome of plinth material choice is stiffness, mass and damping factor. If you haven't comes to terms with these, choosing materials is really hit and miss (mostly miss).
Materials that have very little intrinsic damping are not going to be useful (except to look at) for audio work where damping vibrations are necessary, whether for turntables, loudspeakers or shelves.
So testing materials, even small ones, as long as the dimensions are within the ASTM or ENV guidelines, are very useful (and indispensable) to choosing suitable materials.
Of course, one could choose materials by how they look, then try to convince yourself you made the right choice.
So - what 'is' a suitable material, or combination of different materials?
This question has been asked several times over the years I've been a member here, and every time someone suggests something, somebody else pops up saying " No-No.."
Some examples would be nice to have. TT plinths of highly ranked models have mostly been wood, except extreme cases.
Also - access to materials vary conciderably over the world. I live in an outpost corner of the world, where ordinary woods and common metals is all I can get, without importing it myself.
And what about damping materials for ordinary plinths? Lead, bituminous plates, sand, caulks, sorbothane etc???
This question has been asked several times over the years I've been a member here, and every time someone suggests something, somebody else pops up saying " No-No.."
Some examples would be nice to have. TT plinths of highly ranked models have mostly been wood, except extreme cases.
Also - access to materials vary conciderably over the world. I live in an outpost corner of the world, where ordinary woods and common metals is all I can get, without importing it myself.
And what about damping materials for ordinary plinths? Lead, bituminous plates, sand, caulks, sorbothane etc???
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