Sigert wrote on Mon, 06 April 2009 19:55 |
What about impedance vs. reduction in dB SPL? Do the results from my graph seem credible?
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On impedance VS reduction (in simplified terms): for sound to be "blocked" it implies a change of impedance. This happens when the energy meets a different surface (see isotropic vs anisotropic environments btw) with an impedance different of the air's impedance (or of the original transmitting medium). In this case when the energy goes in contact with the new surface, we are first talking of the "surface impedance" of the new medium. Part is (not always!) reflected (or diffracted) and part is transfered to the new medium which will tranfer it to adjacent materials, re-emit and there will be some loss in heat too. All depending on surface impedance and core impedance.
In this new "x" medium the energy will for ex "slow down" like in rockwool (resistance to flow), or "accelerate" like in concrete or metal (or water). Among other things, the denser (so the higher the impedance) the "faster" and vice versa.
http://en.wikipedia.org/wiki/Speed_of_soundBut what you ask is pretty straight forward and is more linked to mass: higher mass implies higher reduction. But what does higher mass imply in terms of impedance?
See where I'm going?
Your graph is a lil weird...