DIY Speakers and Acoustic Panels

DM60

Well-known member
Here is a guy who is really good at looking at different stuff from a technical perspective. I think it is worth watching and informative to this board.

Let me know what you think.
 

mjbphotos

What?!?
I work with gases. The only way to 'flush' the cabinet with helium would be to have an exit port and would take overpressurizing, pushing air out multiple times. Helium atoms are small - they will diffuse out faster than air, so his numbers really don't mean much in that part of the experiment. But it was interesting that all the different speaker designs made very little difference.

The materials analysis of the various types was more interesting. Never heard of using TP! Not surprising results using rockwool, and interesting that adding foam to roxul was not good. I'd like to see him do it with OC703/705.

Keep this youtube bookmarked to share the next time someone here suggests egg cartons!
 

Folkcafe

Active member
I was recently reading about how the Navy built an anechoic chamber with no absorptive materials at all. It is constructed entirely of stainless steel wedges. The biggest flaw I see in this video is it completely ignores the biggest challenge studios have with treatment, bass. Low bass especially.

Absorptive materials effectiveness is factored on a number of things. The above suggestion about 703 & 705 would be illustrative of one factor. As the thickness of these materials increases, you get to a point where it becomes reflective vs absorptive. After 4 inches this becomes the case with rigid fiberglass and light density pink fiberglass outperforms it at lower frequencies. The rating you need to be aware of is gas flow resistivity. If you know this density spec, you can enter it into this calculator and compare performance. acousticmodeling.com

So for instance OC EchoTouch R19 has a rating of 2900 and OC 703 is 18000. Plug those numbers into the calculator and steadily increase the thickness without an air gap and watch the graph change as it gets thicker.

Note for clarity, should read lighter density insulation which would include lower density semi rigid first and as you go thicker, light density pink fluffy stuff. It is a point of diminishing returns at thickness and materials for use has to be considered in the equation.
 
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DM60

Well-known member
I work with gases. The only way to 'flush' the cabinet with helium would be to have an exit port and would take overpressurizing, pushing air out multiple times. Helium atoms are small - they will diffuse out faster than air, so his numbers really don't mean much in that part of the experiment. But it was interesting that all the different speaker designs made very little difference.

The materials analysis of the various types was more interesting. Never heard of using TP! Not surprising results using rockwool, and interesting that adding foam to roxul was not good. I'd like to see him do it with OC703/705.

Keep this youtube bookmarked to share the next time someone here suggests egg cartons!
Or foam panels!

I posted because it supports, long winded, everything that is stated on the board.
 
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