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In Reply to: RE: Looking for experience in damping material posted by Mushroom Soup on March 01, 2013 at 12:51:48
For my TD125 I made an arm board of a plexi-lead-plexi sandwich, epoxied together. I think the lead was 1/8" or so. Very easy to make: you can cut the lead with big snips, and the plexi is easy to cut and trim (use a small rasp plane to smooth the cut edges.) I think I got the materials on ebay. Merrill used to make an add-on lead platter mat, which I epoxied to the outer platter after making a jig to get it centered. I replaced the springs with 1"(?) sorbothane spheres, which made a huge improvement in imaging, at the cost of less feedback isolation, so I spiked the whole thing. (The spheres get better after a few years as the sorbothane squashes more and gets a little firmer.)
I haven't opened it up in ages, but seem to remember cutting a few lead sheet pieces to glue to the subchassis cast aluminum parts.
WW
New Orthophonic High Fidelity
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Huh. I've got some lead like that -- I got it to put under the bridges on electric basses. It would be a bit thick for this application, though. Maybe I'll go look for some 16ga or so.
It is often sold for Roof flashing - and is reasonable to work with...
Happy dampening
Sorry but I have to be a noodge.The phrase is damping. Dampening means to make something wet. Hmmm ... No I won't go there!
Edits: 10/16/13
I haven't made anything wet in years.So I'll stick to Damping.Come to think of it I haven't done much in years.
According to my sources (the dictionary), dampening has several meanings.
v.tr.
1. To make damp.
2. To deaden, restrain, or depress: "trade moves . . . aimed at dampening protectionist pressures in Congress" (Christian Science Monitor).
3. To soundproof.
None those definitions have anything to with reducing mechanical vibration; in mechanics it is damping .However, in acoustics you can provide dampening of sound waves traveling through air.
So for example ... if you do not provide adequate damping of vibrations in your machine, you may have to provide some type of acoustical dampening to eliminate the sound produced.
They are related but different phenomenon with different nomenclature.
It's kind of like the different terms effect and affect .
Where as ... if you do nothing to mitigate the effect of alcohol, you may feel like your judgement is affected.
I remain ... the noodge! :-)
Edits: 10/17/13 10/17/13 10/17/13 10/17/13 10/17/13 10/17/13
You wrote,
"None those definitions have anything to with reducing mechanical vibration; in mechanics it is damping."
You also wrote,
"However, in acoustics you can provide dampening of sound waves traveling through air."
Acoustic waves ARE mechanical waves. Hel-loo!
:-)
No they are not the same as you infer. They are very different. And I didn't refer to mechanical vibration as waves. However I will now in terms of properties.
Mechanical vibration can be transduced into acoustic waves and visa-versa.Mechanical vibration can exist in a vacuum where acoustic waves cannot. The classic example of a bell ringing in a vacuum chamber; the bell vibrates mechanically, but there is no transduction into acoustics waves since there is no air.
Mechanical vibration is mostly expressed as transverse waves, sometimes surface waves and sometimes longitudinal waves.
Acoustic waves are exclusively pressure waves and are almost always longitudinal waves.
Again, the reduction of energy of mechanical vibration is damping.
The reduction of energy in acoustic waves is dampening.Two different terms for two different types of energy state changes.
By the way, reduction of energy in an electromagnetic wave is called loss.
All of these energy transfer modes and the reduction of energy in each can be referred to under the broader term, attenuation .
So feel free to use attenuation, it's much less specific or apparently less problematic. :-)
Edits: 10/20/13 10/20/13
If dampening is ok for acoustic waves it's ok for mechanical vibration. They're both mechanical. Don't get so hung up on semantics. Remember, it's only a hobby.
Cheers
Very cool, thank you.
If you don't like the idea of working with lead you could try stuff like this:
nice work and a lot of it or so it seems. Nice website too
Stu
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