Too busy to deal with all of Dan's good points, so I'll do that later or tomorrow. But I have just enough time now for this:
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Originally Posted by
Weasel9992
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they can't even agree on what constitutes "proof".
Yes, and this is why I asked above for clarification on what sort of practical tests we can do that will be accepted. Once we agree on a test, the rest is downhill!
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you threw out Bryan's assertion than the surface reflection properties extrapolated to a larger scale ... please explain how Bryan was wrong to begin with.
Sure, glad to. I'm sure most here understand the concept of absorption coefficient, and how it differs from sabins of absorption. An absorption coefficient is a dimensionless spec. For whatever size sample you have, you get some percent amount of absorption. Reflectivity is exactly the same. Indeed, it's the
reciprocal of absorption. If a sample is one square foot, some amount of the sound is reflected. This too is a dimensionless spec.
Now, we all know that a large empty space has more reverb, and longer reverb, than a bedroom. But in the context of discussing reflectivity, that's an unrelated issue that just confuses things. It's much more sensible to stick with the "coefficient" concept which is dimensionless to stay focused on the one attribute that matters - loudness of the reflections at different frequencies. So whether a wall is 10 square feet or 100 square feet, sound in the room will strike the wall and be reflected by some percentage versus frequency.
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True, the scale remains the same relatively speaking, but the net result is much, much larger.
Yes, but again this happens regardless of the surface types just because large rooms have more reflecting surface area, and thus more reverb, than small rooms. This is unrelated to the percentage of reflectivity, and so is best omitted from the discussion.
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The difference is that .14dB is not audible where 3dB most certainly is.
Right, but this is exactly why applying scaling is wrong in this context. If the entire room is cement first, then lined with wood, the difference in reflected sound will be 0.14 dB (or whatever) regardless of the room size. Yes, the total amount of reverb will change, but not the
ratio difference between cement and wood
Since the data my "reflecting" formula is based on is dimensionless, how could one know how much to multiply the dB values by for 10 square feet? Or 1000 square feet?
--Ethan