I live in a unsymmetrical duplex and my HT room happens to share the wall. I am thinking of getting some acoustic foam on that one wall.. approx 10'x8' high. I was wondering if that would mess up my speaker's sound imaging, but the speaker on that side is 2' away from the wall and pointing at me anyway..

Also how much sound is transferred to the attic? when I am up there it is hard to yell through because of the insulation already, but I am sure at movie volume it would have some sound going through. I want to minimize the impact because my attic connects to the bedroom of the neighbor (2 stories, where my side is 1 story), maybe some foam there would help as well.

Do acoustic foam have to be certified to leave in the attic as for as fire code, flammability etc?

Thanks in advance!

OK, did some reading here, sounds like egg crate foam isn't really intended to do this. I guess I can forget about it and save the $ towards another house..

Acoustic foam, or any porous sound absorber, is going to do very little to block sound. Low frequencies are the hardest to isolate.

And then of course there is this problem for cheap foam products:

http://apps.cityofbeaufort.org/depts/fire/images/TheStation.jpg

Isolating sound is very hard to do after walls are constructed. You might try posting on the Dedicated Theater Design & Construction forum, where the serious sound isolation folks hang out.

- Terry

true, I have read about toxic fumes when most foam burns up, I think I will stay away from doing this.