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Lonely Raven · 29th December 2009

OK, so I have a problem, and I was flipping through a stack of acoustics books skimming for ideas. Tell me what you think might be a solution to this problem.

I have a projection screen in my home theater, it's a 10' diagonal, and made from white counter top laminate (about 1/16" thick), held in a wood frame, with one brace down the middle.

Now, the whole thing resonates at somewhere around 15hz to 20Hz, I've not pinned down the exact frequency, but it's in there. I originally thought to use some 3M 90 strength spray glue and glue some 8pcf Rockwool to the back of the laminate material thinking this would make a giant bass trap and stop the resonating all at once.

But after skimming through some acoustics books, they mention that a panel absorber should NOT have the insulation touching the panel, but be separated by at least 1/4" (if I remember correctly). Which then made me realize, if I pile up some 8pcf insulation on the screen, I'm changing the frequency the screen resonates at...

So, if I make this projection screen into a panel absorber, would simply mounting the Rockwool to the wall behind the screen (screen floats on a french cleat) work, or would it have to be a sealed environment? The book I skimmed didn't mention anything about panel absorbers needing to be sealed, just had some calculations for figuring out your own panels.

Suggestions?

29th December 2009	#1
Lonely Raven Gear maniac Join Date: Nov 2009 Location: Bolingbrook, IL Posts: 230 Thread Starter	Projection Screen Absorber? OK, so I have a problem, and I was flipping through a stack of acoustics books skimming for ideas. Tell me what you think might be a solution to this problem. I have a projection screen in my home theater, it's a 10' diagonal, and made from white counter top laminate (about 1/16" thick), held in a wood frame, with one brace down the middle. Now, the whole thing resonates at somewhere around 15hz to 20Hz, I've not pinned down the exact frequency, but it's in there. I originally thought to use some 3M 90 strength spray glue and glue some 8pcf Rockwool to the back of the laminate material thinking this would make a giant bass trap and stop the resonating all at once. But after skimming through some acoustics books, they mention that a panel absorber should NOT have the insulation touching the panel, but be separated by at least 1/4" (if I remember correctly). Which then made me realize, if I pile up some 8pcf insulation on the screen, I'm changing the frequency the screen resonates at... So, if I make this projection screen into a panel absorber, would simply mounting the Rockwool to the wall behind the screen (screen floats on a french cleat) work, or would it have to be a sealed environment? The book I skimmed didn't mention anything about panel absorbers needing to be sealed, just had some calculations for figuring out your own panels. Suggestions?