# Front wall/Rear wall absorption ideas



## Laidback (Feb 8, 2015)

I have a 16'x26' room. Using AT screen. Going with 7.2 set up. One sub will initially be placed behind the screen slightly off center and the other in the rear of the room (not in the corner) about 8' off of rear wall and 2' off of wall. (next to front row of seats).
So, that's the set up so far (planned anyway). I am planning for the front and rear walls to be all around 8"-9" of pink fluffy covered with a 1x4 framed/covered fabric panels. I was wanting to know if there would be any benefit to adding a layer of plastic (6 mil visqueen) between the fabric panels and the fluffy? I am still stumped about this after reading all over the place. I will have full height corner bass traps in each corner and then 2" absorption panels at a couple of the first response locations and then several other places. The side walls are 12' at the top so there is a bit of bounce to kill off.
Any advice is appreciated.


----------



## Blacklightning (Nov 22, 2011)

Are you able to test the room with REW? You may be trying to fix a problem that is not there.


----------



## Laidback (Feb 8, 2015)

I am hoping to test it this weekend with REW. I have nothing but the front stage and false wall for screen built right now. I just would like to have a plan for the front wall sooner than later due to wanting to button up the front and then test and re-test as I add the riser, rear wall treatment and so on. Right now it is a giant booming box with no carpet.


----------



## bpape (Sep 14, 2006)

No need to go that thick on the front wall - but the side wall reflections could easily be 4" for better performance. If you put plastic on the rear wall, that's fine but not the other 2 locations. Those you want full range, though the lighter the membrane the higher up in frequency it is before it starts reflecting.


----------



## Laidback (Feb 8, 2015)

bpape said:


> No need to go that thick on the front wall - but the side wall reflections could easily be 4" for better performance. If you put plastic on the rear wall, that's fine but not the other 2 locations. Those you want full range, though the lighter the membrane the higher up in frequency it is before it starts reflecting.


I was only going to go 9" because that is the recommended depth on the R-30 fluffy. So I guess it sin't a big deal to compress it a tad to help out conventional framing or fabric widths?

On side wall reflection areas, I have calculated two spots/areas based on front row and second row seating (center) so it really looks like I could just use 3 2x4 panels on each side in the front "half" of the room? I used the mirror drawing technique for the fronts but not sure if it works the same with the side surrounds and rears. I may just end up with 6 2' x 4' panels on each side of the room. Not sure on the ceiling panels yet. I know I can save money if I buy them all at once (16 or so).

I am using the 6lb Roxul in the corner traps. Same stuff in the wall panels? I just like to have a plan in place before moving too far forward.

Any beginner tips on using REW. I have a calibrated mic with the file and all. I think I am good to go once I hook up everything.


----------



## bpape (Sep 14, 2006)

3lb is fine for side walls and corner chunks. Don't worry about surround reflections anywhere other than the front wall.


----------



## ovillegas (Jan 30, 2012)

bpape said:


> If you put plastic on the rear wall, that's fine but not the other 2 locations. Those you want full range, though the lighter the membrane the higher up in frequency it is before it starts reflecting.


So you are saying you want to absorb full range from the side walls and the front? 

Sorry, I'm also trying to figure out the whole sound treatment thing, and I'll probably describe my situation in another thread so I don't hijack this one.


----------



## bpape (Sep 14, 2006)

Yes - reflections for the side and the whole front wall you want to do all the way up.

Nice pic in your signature. Go HAWKS!


----------



## Laidback (Feb 8, 2015)

Got the front wall all done with 9" of fluffy covered by nice thinner black fabric. Also, got the corner bass traps for the front stacked up. I measured the room before and after and it is cool to see the differences. I forgot to run the room correction software after the front was done but I could still see a decent difference. I will try to post after I do the correction (and figure out how to post pics on here)


----------

