DIY Sound Absorbing Panels

   These panels were designed and built in 1988. Since that was 'pre-internet', it didn't occur to  me to photo document the process. At the bottom of this page are links to websites of people that have built and photo documented similar panels

I built the panels and corner bass traps to help control the rear wave room loading from my HT front main speakers. Each main consists of 2-12"X93" Acoustat ESL panels per side. Mounted between each pair of ESL panels, is a baffle containing 16 Technics EAS-400 leaf tweeters, and a B&G RD-75 planar mounted in a dipole configuration. So as one can imagine there is a lot of rear wave to contain.

The absorbers are as follows:

1)  2"x4" frames with the 2"X4"s attached to each other on edge so the frame is 3 1/2" deep
2)  1/8" peg board is attached to the backside with screws, this is used for lateral stability/strength.
3)  The frame is lined with fiberglass insulation, the kind with kraft paper or foil on one side only. Place the insulation in the frame with the "facing" toward the pegboard, and the "raw " fiberglass facing out. Use 6" thick bats and compress it with the mesh
 4) Get "hardware cloth", it's like "chicken wire" only stiffer and has a square grid. Most good hardware or home center stores will have this. Cut a piece the exact size to the outside dimensions  of the 2"x4" frame and attach with staples.
 5) Go to a cloth store and get dacron batting. The 'bonded' batting is easiest to work with, but more expensive. It's used to make comforters/quilts. Stretch a single layer of the dacron over the entire frame covering the wire mesh and extending around the frame edges onto the 2"x4" then staple. The poly batting helps contain the fiberglass fibers, and has different absorption coefficient than the fiberglass. 
6) Get muslin or similar loose weave natural fiber cloth and stretch it over the entire structure; stapling it into the back side edges of the 2"x4" frame.

    These are good for all frequencies. If you want to experiment and not absorb the HFE, then temporarily put thick plastic drop cloth on some areas. It should be placed between the dacron and the outer covering material. This will cause the panels to reflect HFE.

I would suggest making 2'x94" panels make 4 to start with, place them around the room and listen to the results.

    In the corners of my HT, I used the same approach, but made quarter round columns with a 24" radius and a height of 46". I made 4 of these, and have them stacked 2 high in each corner behind the mains. The columns have OSB top, bottom and sides. the arc is supported with 2x2's. Then the same, stuffed with fiberglass, wire mesh , etc. These are used specifically to control the bass waves in the corners of the room behind the mains.

    Remember the panels and columns can be any size or shape.  Nothing is gained by making the panels deeper than the width of the 2x4. Also you can use any cloth that has a fairly loose weave. If it has a tight weave it will reflect HFE.

    I have some panels attached to the walls, and some, at an angle on the floor, just leaning on the wall. Experiment see what sounds best.

    I have helped "tune" the listening rooms of several friends with these panels. All were very satisfied. Some just bought 2- 4'x8' pieces of pegboard, had the home center cut them in half  lengthwise and then build the frame around that. I think having more of  the 2' wide panels, is more flexible for experimentation.

    For rooms not needing this extreme level of control, or for fine tuning, the home center stores have panels made from compressed fiberglass. These are easily attached to the walls. Keith Kidder has a website describing how to make these. To absorb lower frequencies these panels should be spaced out from the walls several inches.

Additional information on other DIY panels/DIY Room Tunes, is available on Jon Risch's website. Some very simple to make bass traps are detailed HERE. Pat's DIY sound absorbing panels are described HERE. Chris Tsutsui's DIY panels are documented HERE. And photos of Dennis J's DIY panels are HERE

 

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