I'm building some Deep Bass traps using the well known article by Ethan, "Building A Better Bass Trap" but I'm not sure what thickness wool to use. The diagram indicates 1" thick, but the parts list says "Each" deep bass trap requires:
2 pcs. 2' x 4' x 1" Owens Corning 703 rigid fiberglass @ $0.62 / square foot = $9.92
That seems to imply 2 layers. The updated price list also shows 2 pieces. Is my geometry calc off, or is this too much wool?

Also, is the thickness and type of dense fiber glass critical, because I have some 705 as well as 703 and might experiment a bit?
Thanks,

Either 703 or 705 1-inch thick is fine. Two pieces are shown because those traps are 8 feet high. So the pieces go one above the other, not sandwiched to be thicker.

--Ethan

Thanks Ethan.