AsOriginallyRecorded wrote: ↑
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. :)
well, with all due respect, I suggest that you are incorrect. Googling "do vibrations travel" brings up umpteen opinions on wave propagation in air. Your suggestions about traveling through various materials is not correct, however.
If a slab of material (a plinth or support) is excited, it will vibrate according to very well defined ways, depending on various parameters and edge effects. A single board (lets say of wood, but it applies to virtually any material) will vibrate at its fundamental frequency, the lowest (usually) and behave in exactly the same way with any material and any size (down to nanometer dimensions). Then there will be harmonic vibration, depending on the foregoing. The shape of the deflection is a sine wave, viewed from any edge. The size and shape of the board help determine the wavelength at which the board vibrates. Other variations are determined by how the edges are configured, be it clamped, free, simply suspended or guided. All this has been well known for decades, and various mathematical models have been developed to validate it (or visa verse
). This is all in the scientific press, written by scientists and verified by scientists, not audiophile opinion.
The science of different materials put together is well understood by scientists, although not by audiophiles, it would seem. If slabs of materials (scientists call them plates) are just placed one on top of the other, then mechanical impedance comes into play. If the various materials are glued together, then a new (glued laminate or glulam) is formed, and all layers vibrate together, in the same direction, at the same time, at the same frequencies. There is no reason why gluing several disparate materials together would get you what you need, and prayers won't help.
I would suggest the principles are not easily understood, evidenced by your misunderstanding, but methods of damping are. Mileages will not vary! If you have had 'success' by your methods, then if you believe that there has been an improvement, so be it, I am happy for you. But don't suggest an untrue description of what you think is happening, that is how urban myths are started, and there are more urban myths in hifi than truths.
The problem with not understanding the physics is that one comes up with alternative ideas, which are not the facts.