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Old 24th May 2020
  #6
Lives for gear
 

Quote:
Originally Posted by Starlight View Post
Can I just stop you for a minute?

You asked (here) about foam before and avare said it without mincing words:

Rather than continue that discussion
There was no discussion to continue. The advice given was "go read a book", and was done so in a dismissive way. The actual question was not answered.

Quote:
you started another about foam and fabric (here) about which I asked you:
The question was not about foam. It was about fabric... completely different topic.

Quote:
Rather than answer that question...
I didn't see the point in answering a deflective question. My question was about fabric, not about justifying the use of foam. But if it humours you, I went back and answered the deflective question.

Quote:
If your intention is to keep starting new topics until you hear what you want to hear
My goal is to fit my understanding to known data, not the other way around. Misses in acoustics are expensive in time, money, environmental waste, and space. Acoustics is mathematical and doesn't care about my opinion or anyone else's. I'm seeking the science.

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- that foam, cardboar and foamular are ideal for acoustics - then I fear you will be dissapointed. If, on other hand, you are open to hearing what works best and what is the best value for money then here is one of the right places.
My two questions on this topic (never actually answered on the forum at the time of this writing, which is o.k.) have always been about *airspace*... not the materials comprising the panels.

Quote:
I am sorry to be the bearer of unwanted news.
There is no need to say you are sorry, and there is no possibility for unwanted news, unless the news is inaccurate. This is because, as explained earlier, I don't seek a pre-desired answer to my question... only accurate news is desired. And that news was never given at the time of this writing (i.e. the question was never answered).

I found this in the Alton Everest book:
"The mounting method has a major effect on the absorption characteristics of the material. For example, the absorption of porous materials is much greater with an airspace between the material and the wall."

Also from the Alton Everest book:
"Effective low-frequency absorption can also be achieved by spacing the porous absorbent out from the wall. A spaced porous absorber can be as effective as a non-spaced absorber of the same thickness. This is an inexpensive way to get improved performance—within limits."

I saw corresponding airspsace-is-good statements repeated among several acoustics materials companies, and did not find any other academics or industrial entities with contrasting statements. So my conclusion, based on statements of multiple professional sources, is that a reasonable amount of airspace behind an absorber panel is not harmful, and is even helpful.

Last edited by gearstudent; 24th May 2020 at 10:37 PM..