# New wall and front wall



## MX48 (Oct 11, 2009)

I am closing off my HT room with an interior wall and have a couple of questions.

1. The new interior wall is 20 Ft. Should I add any insulation inside the wall? I live alone so am not concerned with sound leaking. Is there any acoustical advantage to putting some in there?
Edit: I did some more searching and it seems that I do not need to insulate the wall if I don't care about keeping the sound in.

2. From what I have read here the front wall should be completely treated. Is there an inexpensive way to do this? The room will be 11 ft. wide when the wall is finished. I would rather not glue anything to the wall if I don't have to. All corners will have bass traps, the back wall will have probably two 6" bass traps, and I will have two 2" panels on each wall and ceiling for first reflection. Treating the whole front wall with panels would add a significant expense.

Thanks
Moto


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## bpape (Sep 14, 2006)

Welcome

1. That's absoutely false. You absolutely should insulate the wall. in addition to helping mitigate sound transfer, it also allows the wall to act as a broadband bass absorber. In addition, if the wall is not insulated, it will ring and resonate like crazy. It's a cheap thing to do, go for it.

2. Treating the front wall does add an expense. The reasons for doing so are:

- Keep surround reflections from contiminating the front soundtage.
- Help with boundary related bass issues (SBIR)

If you don't want to glue anything, you can make some simple framed panels to hang on the wall. Get some cheap, cheap ceiling tiles and pull of the facing. Use at least 2 thicknesses. While these won't be all that great for the boundary issues, they'll at least be effective to maybe a few hundred Hz in terms of killing reflections.

Another option is to use some thin insulation tacked to the wall by the ceiling and hang a cloth over it from a tension rod.

Bryan


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## MX48 (Oct 11, 2009)

Thanks Bryan.
I will definitely insulate the new wall.

Any specific thin insulation and cloth that I should use for the front wall?

Thanks
Dan


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## bpape (Sep 14, 2006)

Well, if you can find like an R6, that would work - or like I said, some cheap (fiberglass back with vinyl facing) ceiling tiles that you can double up and pull off the vinyl facing.

Cloth - most people use Guilford FR701-2100 408 black - but it's not cheap. You can also use black muslin if you can find it.

Bryan


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## eugovector (Sep 4, 2006)

From the prices I've seen at my local hardware stores, you'd do just as well to get some 1-2" OC703 (and less mess with pulling off the vinyl). But, your market may have the panels cheaper.


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