Opinion on one or two layers of Linacoustic RC 1" behind false wall. - AVS Forum
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post #1 of 9 Old 11-10-2013, 09:41 AM - Thread Starter
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I'm in the middle of installing Linacoustic behind what will be the false wall in my copycat theater. I'm wondering what will be the gain with installing two layers vice one?

I'm trying to stretch my 100' roll of 47 1/2" to cover my entire project. Two layers on the side, back, and ceiling walls will require ~ 94 linear feet leaving me with just 6' for panels. If I can get away with just one layer on sides and ceiling I might just have enough for the whole project.

Does any one in Northern VA have any leftover Linacoustic your looking to unload? I'd hate to purchase another 100' roll.

Thank you in advance for your assistance.
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post #2 of 9 Old 11-10-2013, 10:23 AM
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I'm not really qualified to give you specific recommendations, even after you provide some more details - that said...

It has to do with what frequencies you need to absorb - lower frequencies mean don't skimp on the thickness. Determining what frequencies you need to absorb has a lot to do with your speaker choice, and placement. You may conserve effectively by limiting the double layer to the regions nearest the main channel loudspeakers (for SBIR). You may also conserve if you take some out of the corners and replace it with a more traditional bass trap - you wouldn't need linacoustic behind your bass traps.
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post #3 of 9 Old 11-10-2013, 11:11 AM - Thread Starter
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Thank you for the idea--I didn't think about conserving in the corners. Would it hurt if I placed corner chunk type traps in front of the Linacoustic?

I really wished I payed for an acoustical treatment design. I figured I would just treat with some of the common measures I have read about here and deal with any issues after the fact.

My room will roughly look like this with Paradigm Studio 100s and 2 CHTs SS18.2s behind the false wall.

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post #4 of 9 Old 11-10-2013, 11:48 AM
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Per both Toole and Erskine. Fiberglass insulation in front corners for the purposes of bass trapping is waste of money. At the front corners standing waves are at their highest pressure level but lowest velocity. Fiberglass is a velocity bass absorber. You want to make a dent on bass you need membrane absorbers. Of course you should know what frequencies you need to tame because membrane traps are effective over certain frequencies. So what to do? Put a layer of 3mil plastic between the two layers of linacoustic on the front wall and it will behave as a membrane trap of sorts. cross your fingers and hope for the best.

You also don't want more than 25% absorption coverage of the side and rear walls in total, think about some areas to use diffusion instead Like the first reflection points. You can also use scrim in some areas to keep from over dampening the room.
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post #5 of 9 Old 11-10-2013, 12:54 PM
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Looks like you wouldn't save much by keeping the linacoustic only behind the speakers - maybe a foot or so in the corners. For handling SBIR, treat any surface within 3 feet of the speaker with at least 2" - and the plastic is appropriate as BIG said.

To BIG's point about the bass trapping - it's a totally fair point. The good news for you is that you have a smaller zone of seats that needs to be optimized for, and it's at a good position already - about 55% back in the room. Putting your room dimensions into a room mode calculator, it looks like you'll have some fairly strong modes bunched in the 60-70Hz range. A bass trap tuned to that range would be a good idea - maybe along the rear wall, outside the columns. Further, as BIG said again, some diffusion would probably be the best choice for first reflection point. While some designs would make good use of the linacoustic in a hybrid design, you probably have enough.

Of course, that's just my opinion, which is worth exactly what you paid for it. smile.gif
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post #6 of 9 Old 11-10-2013, 05:31 PM - Thread Starter
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A big thanks to both of you! smile.gif

Big - Do you have a hole in your schedule yet? I've been creeping along using the Beam and Pole thread for guidance.

Rich with Falcon Screens should be here next Saturday with a 130" scope screen and masking, I hope.

Not exactly sure how to implement diffusion or even what is scrim, but I'll look into it here on AVS.

Also, do I use spray adhesive to attach the 3 mil plastic between the two layers of Linacoustic?

I want to make sure I can place my subs behind the screen which are 22 inches deep without pushing the screen too close to the recess lights. This project seems like a game of inches.

Thanks again,

Shawn
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post #7 of 9 Old 11-10-2013, 06:03 PM
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post #8 of 9 Old 03-20-2014, 06:51 PM
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Quote:
Originally Posted by Wahoo_envy View Post

I'm in the middle of installing Linacoustic behind what will be the false wall in my copycat theater. I'm wondering what will be the gain with installing two layers vice one?

I'm trying to stretch my 100' roll of 47 1/2" to cover my entire project. Two layers on the side, back, and ceiling walls will require ~ 94 linear feet leaving me with just 6' for panels. If I can get away with just one layer on sides and ceiling I might just have enough for the whole project.

Does any one in Northern VA have any leftover Linacoustic your looking to unload? I'd hate to purchase another 100' roll.

Thank you in advance for your assistance.
 

 

 

Wahoo,  I was looking at doing linacoustic on my front wall as well.  I'll have an AT false wall 2' in front though, but want to treat the real front wall behind it.  Wondering what did you end up doing?  Did you put two layers of 1" or just 1" thick single layer?  Thanks.

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post #9 of 9 Old 03-21-2014, 12:00 PM - Thread Starter
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I'm hoping to install 3m poly then the second layer this weekend.
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