googacky ) wrote:
hello everyone. i'm getting ready to build some panel traps out of
owens corning 703 and 705. i want them to be portable because i'm not
sure how long i'll be recording in my present (less than perfect)
space. my plan is to build 2 x 4 ft. frames for each piece and cover
the fiberglass with burlap. i'm not sure how best to build the
frames, however. should i build a simple open front box with a piece
of 2 x 4 ft. plywood as a backing or should i make a frame with a few
pieces of plywood spanning the back for structural integrity?

When I made mine, I got my fabric from the clearance bins from Wal-Mart
-- whatever was least offensive among some fierce competition.. I also
bought the poly batting there, to help contain the fibers.

For each panel, I made a frame the same size (or slightly smaller) as
the 703, out of 1x3's with 1/4" plywood backing (for support and fiber
containment). Then:

- I laid precut fabric on the work table, with doubled poly batting on
top of that;
- centered the 703 on that;
- set the frame on top of that, plywood side up;
- then wrapped around and stapled the fabric/batting to the back edge of
the frame.

The result is that the sides of the frame are roughly flush with the
sides of the 703, supporting it but not containing it, if you can
picture that. The 703 and frame are basically held together by
'upholstery'. Having the frame slightly smaller helps minimize the
chance of the 703 slipping inside of the frame if it shifts/bends.

The function of this "frame" is to fur it out from the wall (for lower
end absorption), not for protection. The're also easy to hang, and
reposition. I unexpectedly had to move to a different city, and they
survived the movers just fine (I did explain their design, and how -not-
to pack them). I'm about to move again, and I'm not worried about
durability. If they 'break', it's unlikely they'll be hard to 'fix'.

also, i
plan to use the 705 to build corner traps for my control room. i'd
imagine that these should not have any sort of plywood backing as it
would reflect some sound back into the room and render the airspace
less efficient. correct me if i'm wrong. i'd like to do this right
the first time, so if anyone has any leads on the best way to make
these absorbers, i'd appreciate it.

F. Alton Everest has some good books on acoustics and studio design, and
in some important ways are worth a thousand pictures.

- Brian