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Discussion Starter · #1 ·
I'm planning to build corner bass trap panels, based on what I've been reading, measuring 24" across, using 5" of roxul rht40. They will go floor to ceiling, and I want to do panels because I'm not quite willing to commit to a more permanent built in trap filled with loose batt material. Question is...should I face them on one or both sides with 6 mil poly as suggested in some discussions? My other treatments so far consist of 6( 3 each side) first reflection absorbers 2" thick, 2" standoff, rht 40. Thanks for your interest and help.
 

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It would depend on where in the room you're using them. In the front corners, we'd normally not face them since we want the front to be more absorbent for surround channel reflections. Elsewhere, either can work but as long as you're DIY'ing and it sounds like you have a decent amount of HF absorbent already, I would face all of the surfaces.

Bryan
 

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Discussion Starter · #3 ·
Thanks Bryan. These will be in the rear corners, so I think I will face them with poly. Side note...I was AMAZED at the sound improvement after installing my broadband specular's. I might do a couple behind my mains at 4" thick, and some 2" on the ceiling for the first reflection there, and the room should almost be treated.
 

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Do your reflections as thick as you can. It will then also help with lower frequency phase related problems.

Bryan
 

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Discussion Starter · #5 ·
Ahh, finally. Reviving a bit of an old thread. Time and money and life can slow projects down to a crawl, and today I finally got some time to actually finish the corner bass traps that I have been working on.

The concept was to have effective bass absorption in the rear corners of my theater without committing to a built in loose fill trap that could not easily be removed. I had planned to do 5" thick Roxul RHT40, but in the end, as you'll see in the pictures, I used up some "left over" RHT40 and extended the thickness to 7". Size was 24" across , although the one corner has a ledge so the panel ended up more like 34" wide above and 24" below. The extra insulation was simply added to the back of the frame, and the fabric holds it in place. These panels were quite heavy, so I hung the upper sections with interlocking metal picture hanging clips, and the bottom sections rest on the floor and have tabs that hook behind the upper panels to keep them aligned and straight.

As of yet I have no way to actually measure their effectiveness...another money thing with buying gear for REW use...but I do think that the bass is tighter, punchier, and less boomy through out the room. When I do get the stuff I need for REW, all treatments will come out of the room and progressive testing will begin.


cbt1.JPG
I made the frames the same as my first reflection panels, only using 1x6 this time for thickness.
cbt2.JPG
I beveled the back vertical edges, just to make attaching the mounting hardware a little more practical.
cbt3.JPG
Completed panel, ready for poly and cloth.
cbt4.JPG
I did face the panel with 6 mil poly to limit high frequency over absorption.
cbt6.JPG
Completed panel front view.
cbt7.JPG
Completed panel rear view. Here you can see the extra layer of RHT 40 being held by the cloth.
cbt10.JPG
Upper right mounted and ready for action.
cbt11.JPG
Upper left with the shelf and added width.
cbt12.JPG
Right side complete top to bottom.

Hope this helps anyone thinking about DIY panels for a theater. The project was relatively simple from a construction point of view. And there is lots of good advice here on HTS as far as thickness and materials is concerned. Enjoy.
 

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Looks great. Let us know how the improvements help.
Thanks for sharing.
 

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6 mil refers to the thickness. Poly is a short term for a thin layer of plastic. Imagine something like a thicker version of a plastic wrap used to keep food fresh after opening.

Bryan
 

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Discussion Starter · #11 ·
Ya what Brian said. 6 mil poly or plastic sheeting is the standard we use in house construction as vapor barrier between the insulation and the inside finish of the rooms(usually drywall). For plastic sheet it's quite thick but still comes on a roll. If you look at pix 3 and 4 above you'll see bare insulation and then with the poly. It's thick enough to reflect high frequencies, but not so thick as to prevent the lows from passing through. I'm not sure what you'd call it I'm German. 6 mil refers to the actual thickness-6 thousandths of an inch I believe.
 

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If my research is correct?

6 mil = 6 thou (thousandths of inch) = 150µm = 150microns = 600 gauge(Europe film measure)

Popular sheet thicknesses in UK(Europe?) are 125µm and 250µm (500/1000 gauge respectively)

So 125 is closest being approx 5 mil thick

Hope that helps:dontknow:
 
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