Thank you, oldhvymec, made my day. How right you are.
mahgister-
Yes indeed we are on the same page. As you well know. And as will become even more clear as the story unfolds.
We left off with the turntable stand. https://systems.audiogon.com/systems/8367 This was based on everything learned in those two years of testing out what was around at the time. Remember again, have to keep reminding people, this was before the internet. Now you just change your browser from Goolag to one that actually works and find what you want in no time flat.
At this time, based on everything tried, I had come up with my own working principles of vibration control based on stiffness, mass, and damping. Stiffness in materials gives a faster sound. Mass improves bass extension and impact. Damping lowers background noise. Each of these also has its downside. The trick is like mahgister said to find the right balance.
What I came up with was solid concrete, with a sand bed cast into it, and granite on top. The idea being the sand will damp the stiff and massive concrete and granite.
Seemed like a good idea until the granite came and holy crap granite rings like a bell!
Important Lesson Number Two: Shape matters! A block of aluminum seems pretty inert, an empty aluminum can doesn't ring either. But what's a tuning fork made out of? Aluminum. And those things ring and ring like forever. So shape is really important too.
Thinking fast, what if the three solid concrete shelves are bolted solidly together? Take ABS, fill it with concrete, with bolts cast in so they screw into matching threaded inserts in the shelves. Super strong, stiff, and massive, now also damped by virtue of the bolted together columns. When bolted together its almost like one solid block of concrete.
It worked! The whole thing bolted together and with the granite on top weighs in around 700 lbs. Its pretty dead too. The sand bed however turned out totally inadequate to control the granite ringing. You could hit the granite and hear it, "ting". Not "tiiiiinnnngg" like before. So better. But still.... So I got another machinists plate and put it on top of the first one, with a layer of Blue Tack in between. A sort of reversible constrained layer damping. That's why there's granite on top of granite here.
This by the way is exactly what mahgister is talking about. No one material by itself has exactly the perfect set of properties we want. By trial and error, and with a lot of serious listening, they can be matched together to get whatever balance of sound we are looking for. Or close as we can, given limited time and money. ;)
mahgister-
The impactful results of resonance/vibration controls embeddings is very audible....The problem is the way to reach results is a complex problem...
Yes indeed we are on the same page. As you well know. And as will become even more clear as the story unfolds.
We left off with the turntable stand. https://systems.audiogon.com/systems/8367 This was based on everything learned in those two years of testing out what was around at the time. Remember again, have to keep reminding people, this was before the internet. Now you just change your browser from Goolag to one that actually works and find what you want in no time flat.
At this time, based on everything tried, I had come up with my own working principles of vibration control based on stiffness, mass, and damping. Stiffness in materials gives a faster sound. Mass improves bass extension and impact. Damping lowers background noise. Each of these also has its downside. The trick is like mahgister said to find the right balance.
What I came up with was solid concrete, with a sand bed cast into it, and granite on top. The idea being the sand will damp the stiff and massive concrete and granite.
Seemed like a good idea until the granite came and holy crap granite rings like a bell!
Important Lesson Number Two: Shape matters! A block of aluminum seems pretty inert, an empty aluminum can doesn't ring either. But what's a tuning fork made out of? Aluminum. And those things ring and ring like forever. So shape is really important too.
Thinking fast, what if the three solid concrete shelves are bolted solidly together? Take ABS, fill it with concrete, with bolts cast in so they screw into matching threaded inserts in the shelves. Super strong, stiff, and massive, now also damped by virtue of the bolted together columns. When bolted together its almost like one solid block of concrete.
It worked! The whole thing bolted together and with the granite on top weighs in around 700 lbs. Its pretty dead too. The sand bed however turned out totally inadequate to control the granite ringing. You could hit the granite and hear it, "ting". Not "tiiiiinnnngg" like before. So better. But still.... So I got another machinists plate and put it on top of the first one, with a layer of Blue Tack in between. A sort of reversible constrained layer damping. That's why there's granite on top of granite here.
This by the way is exactly what mahgister is talking about. No one material by itself has exactly the perfect set of properties we want. By trial and error, and with a lot of serious listening, they can be matched together to get whatever balance of sound we are looking for. Or close as we can, given limited time and money. ;)