AMPS
Do It Yourself Sound Absorbent Acoustic Panels for Your Home
Two of the Finished Panels Mounted on the Right Side of my Listening Area
A Little Cutting Here, a Little Stapling There, and  Voilà!
In the years we've been writing these newsletters we've shared lots of recommendations and advice. Well, like they say, talk is cheap. So it occurred to us that actually doing one of our recommended projects and documenting it for you might be kind of like putting our money where our mouth is. Or putting our hands where our keyboard is. Or maybe ... never mind, you get the picture.  

Acoustic Room Treatments

So, you have carefully followed Sandy's Setup Tips and tweaked your system to the max for the best sound in your room. It sounds spectacular, but, is there more? Well, yes.... Among the most overlooked ways to enhance residential sound systems, acoustic room treatment has to be number one. Although many typical residential rooms aren't acoustically terrible, there's little question that properly placed acoustic enhancements can make notable improvements. If you were to go "whole hog" on room treatment, many experts recommend roughly 50% of the room be reflective, 25% be absorptive and 25% be diffusive. But fear not, we're not talking about anything that dramatic here.  

In past issues we've mostly commented on sound diffusers and absorbers. Diffusers are objects that scatter sound reflections. A reasonable analogy would be a broad beam flashlight aimed at a well shattered mirror with all the pieces of glass still in the frame. There'd be lots of scattered reflections throughout the room. Look at sound diffusers on line and you'll see the analogy fits pretty well. If you're interested in sound diffusion, in addition to commercially available diffusers, there are some on-line plans for do-it-yourself models.

This link is to one source for both, plus other acoustic treatment products; there are other sources and more links at the end of the next article too.
Our Project - DIY Acoustic  Absorber   Panels ...

Gathering The Materials

For our project we chose to build easy to make sound absorptive wall panels at a very reasonable cost. These should reduce unwanted reflections potentially enhancing clarity, definition, imaging and sound staging. After some on-line research we found that Owens Corning 703 rigid fiberglass sheets are highly recommended for this purpose. We purchased a 6-pack of 48"x24"x2" panels along with other project related items detailed below directly from ATS Acoustics.

The thicker the absorbent materials are, the lower the frequency they'll absorb. One-inch fiberglass will be limited to higher frequencies while two-inch material will absorb down to approximately 250 Hz and thus well into the critical midrange. You'll need four-inch thick panels to get down to lower frequencies. NOTE: You can extend the lowest frequency absorption of any material by mounting it "off the wall" using spacers of some sort. We found a couple of sites that sell metal mounting hardware designed to do just that, but small wood blocks will work just as well.

Our box of 703 panels cost us $65.00. We also ordered 5 yards of neutral beige open weave burlap fabric to cover the panels at a cost of $6.00 a yard. Total price with shipping was $95.00. We also ordered metal "spike" plates to mount the absorber panels to the wall. Our pine wood frames were pretty light, but, instead of two mounts per panel we chose to use four. Each pack of 4 plates cost us $2.00 apiece, one pack for each of the twelve 2'x2' panels.

Next we were off to the local lumber yard to pick up eight foot 1"x 2" "furring" strips. (you'll probably need to pick through dozens of boards to get straight, solid examples). They cost us $1.07 each and since we intended to build twelve 24"x24" panels we bought 16 pieces as the cut sections were going to be 24 11/16" each. We also bought 48 medium size metal internal 90-degree angle corners as shown in our pictures and 200 - 1/2 inch wood screws for frame assembly. (This is a much simpler way to assemble square frames without worrying about angle cuts and fancy joinery. Since no one will see the frames they don't have to be pretty, just functional.)
Building The Prototype and Production Line Ramp Up
We built one prototype assembly by cutting four pieces of 1x2 to the length noted above. We made a right angle jig by screwing two 2" by 2" pieces of wood to our working table at a perfect 90 degree angle. We could then press the corners of our frames into the corner of the jig, mark the screw locations with an awl and pre-drill pilot holes so we wouldn't split the wood (See picture to right). We made corners by overlapping at one end of each board and underlapping the next. We also determined which face was to be the front and made sure we set the front face of each board even with the other boards.

Then we cut one 48" fiberglass panel in half using a new, curved carpet knife and pressed it into the assembled frame. The carpet knife cut like butter and there was no fiberglass residue when we were done. Because the 1x2 is less than two inches wide, about 1/2 inch of the fiberglass stood out from the frame. We decided to keep the extended fiberglass forward of the frame face (See picture to right) so when we wrapped the burlap over it there would be a softened angle to the edge.

We then cut a piece of burlap cloth 30-inches by 30-inches and wrapped it around the frame using a staple gun to attach it to the back. We pulled it tight enough to be smooth across the front but not so tight as to cause any pulled effects on the cloth at the staple points. We trimmed the cloth at the corners and folded it over like a package end (See picture to right). We were satisfied with the prototype so on we went to build them all.

Production Line Ramp Up

It took us approximately 16 hours to make all 12 frames.
First we cut all the wood and assembled all the frames. Then we cut the all the fiberglass and inserted it in all the frames. Finally, we cut all the cloth and attached it to the frames.

We're pretty happy with the finished panels and although they're not beautiful works of art,(we couldn't find a guy named Art to help us, only a guy named Steve) they're certainly not ugly or offensive. Since there are many colors and types of cloth available you can personalize yours as you wish. There's also the potential to make other shapes (rectangles, triangles, round, etc.) depending upon your woodworking skills. Then you can make contemporary wall "sculpture designs" using multiple panels.

Since our wife has finally given up on trying to stop our "audio system decorating" after more than 50 years, she was moderately OK with hanging the panels in our home theater/den. We chose the neutral burlap fabric because it wouldn't stand out so much from our antique white walls. In retrospect, we think we'd like a smoother, more colorful fabric instead and since it's so inexpensive and easy to change, we may redo the panels in the near future. In the meantime, time to put them up and check out the results!
All trademarks and images that appear in this newsletter are property of their respective owners. All contents copyright © GoldenEar Technology and may not be reproduced without written permission.