Isolation Baffle - Sound Proofing
To make my studio more comfortable,
I needed to let air in without letting sound out.
To do this, I built two baffle boxes: one near the floor to let cool air in
and one in the ceiling to let warm air out. The baffles inside the box
force air around sharp turns to decrease the volume of sound waves.
By avoiding parallel surfaces inside the box, I limited the propagation of
standing waves that might actually increase the volume of certain frequencies.
I used 2x8 boards to build the baffles and the frame.
First I cut the baffles.
Each baffle is two inches shorter than the width of the frame to
accomodate two half-inch thick pieces of cellutex soundboard and
one inch for air to flow. I cut five baffles
with 90 degree edges, and four with 75 degree edges
to prevent standing waves between the baffles
(the cellutex covering in the pictures below was added later.)
I traced a hole for the air input on a long piece of 2x8.
Then I traced where each baffle would go.
I drew a line 1/2 inch
around the edges of the baffles and the edge of the board to make sure there would be enough
space for air to travel after the cellutex was added. On the other end,
I left space for the air output hole on the other side.
For the two air holes in the board, I used the plumbing pieces pictured below.
From left to right
they are a floor mount, a screw on cleanout cap and a threaded cleanout.
I measured the length of the board that I had drawn the baffle outline on and
cut three more boards the same length. I put two boards on top of each other
and the other two boards on either side. Then I cut two small pieces for each end.
I placed each baffle piece in the trough, drew a line across them at the height
of the side boards, and cut the baffles to that size.
I screwed the end pieces onto the side pieces. I rested the bottom and
top boards in place so the frame would hold its shape and everything would fit
snugly. Then I removed the top, placed each baffle where I had
traced them earlier, and screwed them to the side boards. I removed the bottom board and
used it to trace a piece of cellutex the same size as the board. I placed the cellutex
back under the baffles with the board beneath it for support. Then I traced
the outline of the baffles on the cellutex.
Next I used a drywall saw to cut out the shape of the baffles on the cellutex.
I cut the air hole circle out of the bottom board and used the hole in the board
to trace the hole on the cellutex.
I turned the baffle box over, placed the cellutex piece over the baffles
and trimmed it to make it fit. Then I traced and cut an
identical piece for the other side bearing in mind that the air hole has to be
on the opposite end.
I put the board
on top of the cellutex and turned the baffle box over again. I screwed the
cellutex to the board with 1 inch dry wall screws. I fit the clean-out pieces
together, put it through the air hole and screwed it down with 1 & 1/2 inch
dry wall screws.
Next I cut the cellutex to go on the baffles.
I measured their length, and their height minus a half-inch to
allow for the cellutex on the top board.
I unscrewed the baffles one at a time and screwed on the cellutex pieces.
Before I screwed the baffles back in, I applied wood glue to the bottom of them
and a liberal bead of a silicone caulk that's normally used for windows and doors.
Once all the baffles were back in place and I had wiped all the excess caulk and
glue from the edges, I cut pieces of cellutex to go around the sides
of the baffle box and screwed them into place.
I put all the pieces together to make sure they fit...
...then I applied glue and caulk before screwing them back together.
The ends went on last.
|The finished product: