Originally Posted by NotInvolved
here is a bass trap im building. im planning to put one in my two front corners. what material would you suggest stuffing it with? also, I'm making acoustic panels for my ceiling and walls. i will cover most of the ceiling, and a lot of the walls.
The general rule for optimal stuffing of porous absorbers seems to be that density should be roughly inversely proportional to thickness. IOW thin absorbers are optimal for their thickness with high density absorbant materials such as OC705, while thick absorbers such as this one may be optimal with far less dense materials such as what we see in products for thermal insulation in walls and ceilings.
The best guide that I know of is Whealy's porous absorber calculator which is an Excel spreadsheet that you can download for free from http://www.whealy.com/acoustics/Porous.html
. Note that it handles porous absorbers that are partially empty space which when designed optimally can perform comparably to absorbers that are fully stuffed.
Your best guide is acoustical measurements of how things work in the real world, such as measurements done using Room Eq Wizard, etc.
what type of fiberglass would you suggest for the acoustic panels? how thick should they be?
Proceeding very bravely, and of course with any final design verified by the means mentioned above:
1-2" thick absorbent layer: 705 or equivalent in competitive products including rock wool
2-4" thick absorbent layer: 703 or equivalent in competitive products including rock wool
4-8" thick absorbent layer: 701 or equivalent in competitive products including rock wool
8"-thicker absorbent layer: Insulation batts, possibly somewhat compressed during installation or equivalent in competitive products including rock wool.
Notice that these recommendations overlap somewhat, there are no absolute rules as other aspects of the design and application are relevant.