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Discussion Starter · #1 ·
Finally got around to installing some acoustic treatments and all I can say is what took me so long? Maybe it was the anticipated reaction from SWMBO that was holding me back, certainly not my being lazy or anything like that.:D

I started in the corners with 17x17x24 OC703 floor to ceiling where I could. Beneath the foundation ledge I used 24x24x32 chunks and covered with some black polyester from Jo Ann that I got fairly cheap.. it kinda looks it but its hardly visible anyway. Above I used GOM FR 701 in Rose Quartz for the smaller more visable traps.


So far so good as far as the WAF, and a HUGE difference in BASS response:T

After that I ran out and bought a needed 3rd carton of (12) 2" 703 and proceeded with my next phase.
This is my first 2ft by 6 ft BAD panel enclosure. I did hear a few chosen words from the wife:nono: when I produced this contraption but went ahead anyhow. I made two of these out of some 6 ft particleboard shelving that had been laying around for years. The enclosure will contain 6'' of 703 fronted by 3 - 2x2 BAD diffusors made from masonite paneling with a white face from HD. (one is visible next to the enclosure) I drilled 4' holes on the side for more absorption. .
The blue tape on the wall marks a first reflection point for both of my mains. My system, as you can see, is placed on the diagonal in my 16' x 22' room. I feel having the first reflection point behind my sweet spot is of some benefit and I elected to use some diffusion rather than pure absorption due to this. The room is actually L shaped with a portion extending another 6' and then opening up to the kitchen upstairs. My other two primary reflection points are in the open stairwell and just to right of the piano beneath the open area to the kitchen.


You can see the BAD panel fronts showing through due to the flash.
I have no means of doing any measurements yet but do plan to make some 2x2 and 2x4 absorbers in either 2 or 4 inch for the front wall and at least two more 2x2 BAD panels at my reflection points which will be at either side of the left column type BAD assembly.

So far it all sounds good to me.
 

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Those all look great. You're lucky that your room has the type of architecture that lends itself well to integrating an aesthetically pleasing bass trap.
 

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That is such a cool room, fishinbob, good job! I really like the little nook up the stairs with the table and chairs.
 

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Discussion Starter · #6 ·
Bob, can you give us some more detail on how you created the BAD panels? How did you determine the pattern for the boards? Did you drill them all out individually? They do look good, and I think you've integrated them well.
Thank you,:) I found out about the BAD panels here.

Without access to a CNC I had to drill each 1/2" hole individually and had the blisters to prove it. Initially I made a template out of 3/4 MDF and drilled a hole at each location with a 1/16th bit. This, when placed face down on the material this resulted in a reasonably accurate layout. The bad thing about this was I had to drill twice for each hole. Perhaps a thinner template would have allowed a better method to transfer the layout. Using some sort of marker would certainly be faster. After a short while the tedium of all that drilling takes a toll. I eventually started doing two panels at a time figuring I couldn't drift too far within a 1/4 inch thickness.

I made both 4'X2' and 2'X2' panels and used one of each for the 6 foot enclosure. Nothing special about the assembly. I fastened some thin aluminum angle clips just inside front face to retain the BAD panel edges and spray glued the 2" fiberglass to the panels, overlaping the joints, to make the whole inner assembly more rigid and put a couple of spreaders across the back hold it all in place.
 

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Discussion Starter · #8 ·
Wow, there's a lot of reading on BADs there. Since my head is full at the moment, I won't get into detail on those... I might forget where I live or how to get home! Good bookmark for later though, thanks.
Bottom line is they are so easy to build compared to most diffusers and according to the literature, can be placed much closer to your listening position and still be effective.:T
 

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Bottom line is they are so easy to build compared to most diffusers and according to the literature, can be placed much closer to your listening position and still be effective.:T
Sounds like we need a clear tutorial. Anyone want to draft one, or does anyone have a link that can be posted?
 

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Sounds like we need a clear tutorial. Anyone want to draft one, or does anyone have a link that can be posted?
Drill 1/8" hardboard in the correct pattern, place over absorbing material. Finish to taste.

What I'm really interested in is how to build the curved BAD panels, as they are said to be an even more marvelous acoustic tool. I'd guess that one could just gently bend the 70x board to match, but I haven't seen it specifically mentioned anywhere.
 

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It's too bad the companies who make pegboard can't just tool up to do BADs.
Actually it'd be pretty easy to get woodworking places with NC setups to make the facings, and I think they'd want to more than building material manufacturers as I bet there isn't a big market for parts like that. The patent was issued in Oct 1998 so with the 17 year term, the cat should be able to be out of the bag in four years anyway. I bet plenty of people get them made that way with "friend of a friend" arrangements, or simply sending a woodworker a design without telling them it's a patented item. Though it's probably a gray area in the sense that it's a commercial transaction, one is only really likely to get in trouble if marketing a product or using them in commercially-contracted dealings. If it's a DIYer getting parts made for their own use (but paying for them) it may or may not be technically legally actionable but doing so would be highly unprofitable for the patent holder. Naturally, I am not a patent lawyer (definitely) so no one should take my advice in this area.

There would also be a market for something like pegboard but with lower perforation percentages for use as the face of Helmholtz devices. But it's much like the market for OC 70x - acoustics isn't necessarily a large enough market to accommodate mass manufacturing unless you can use the exact same product for something much higher volume. Unless the acoustics business becomes a much higher volume deal, it's likely to remain a boutique sort of thing. Barring that, it's just easier to use lumber to make slatted versions of the same devices.
 
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