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Discussion Starter · #1 ·
Here is my concept for my new, large on-wall speakers. This concept came about from the desire to have big(ger) sound, but the lack of real space to build large speakers, or to be able to properly place them.

I have begun the build, but was recently laid up with a torn ligament in my shoulder. I am experimenting with some (very) different build techniques, and will post more pics of the real product in the next few days. The center channel is mostly built, the mains are in work.

For reference: The TV is a 52" Samsung, and the drivers are Peerless Mids and tweets with Dayton woofers. (6" on the Daytons, 5.25" Peerless and 1" Peerless tweeters) The finish will be a piano black.


 

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Discussion Starter · #6 ·
I ended up opening the walls so the speakers could be recessed (roughly 4"...1/2" for the drywall & 3-1/2" for the stud). The enclosure I chose is roughly 11" deep with grill, so about 7" of the enclosures are visible.
Yes, I am still considering doing this, as it would allow me to make the mains even deeper. I'm running on the small end of the recommended volume, and doing so would correct this. My CC is more than large enough.

I would most likely just end up making a couple of nooks in the wall that would "coincidentally" be the same size as the speaker. After opening up the wall, it would be easy enough just to shim up to the studs on both sides. The mains are 10" wide, and the wall is a partition wall, with studs on 18" centers. I purposely designed them in a way that allows me to utilize this option. (meaning that I placed them in the design according to where the wall studs fall) Some decorative trim, and off we go...
 

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Discussion Starter · #7 ·
These pictures depict some of the early methods, tools, and prototypes that I created. They were completely hand built, and were meant to be a proof of concept, so to speak. I wanted to make sure that I could build a small scale version reliably enough to dive into the whole design. It works quite well, but I had to leave the router template behind, and instead, had details cut by CNC router from a sheet. (with an open profile - I have to glue the back on, but I get more details now per sheet)







 

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Discussion Starter · #10 ·
If at all possible, try to avoid this kind of step around the speaker - install them flush with the wall or free-standing in front of it. Anything else will result in a very lumpy frequency response, even a gap has bad effects.
I have intentionally drafted the front face of the speaker at 10 degrees off normal, and added 1 3/8" rounded corners to avoid this. The added depth shouldn't take anything away from the compromises that have already been made, and compensated for.
 

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Discussion Starter · #11 ·
Excellent work. I love the idea of using MDF wafers to make unique & interesting enclosure shapes. It's a significant time investment (not to mention the extra MDF), but the result are worth it. Bravo!
Thank you for your words of encouragement. As with all things, I have a few "lessons learned" to share:

1) MDF must be reinforced when stacked. If you notice there are 12 holes around the perimeter of the sections. This is because the MDF stacked - while lacking a true "grain" - still has the effects of cross-grain shear in this configuration. There is a lot of really [email protected] MDF on shelves these days, and the effect is a "layering" or "delamination" effect when transverse forces are applied. (when cut, if you bend it, it breaks almost as if perforated. To overcome this, dowels are placed to bridge the layers, and add strength against bending. (overall stiffness)

2) reinforcements must be staggered. If you don't stagger the dowels, the material will break where dowels end. I used 1/4" all round from Home Depot. It says that it's hard wood, but I don't believe that it is. But that's another story. (it's much more round, and dimensionally stable than Oak) At any rate, half of the dowels should be a couple inches shorter than the other half, to avoid creating a perforation on the same plane. The overlap will correct this condition.

3) Long lengths must be made in sections and joined later. Long bar clamps are a must - but beware, as it's VERY easy to start building a bend into glued sections longer than 20"

4) No matter how nice it turns out, the whole assembly must be sealed after assembly, inside and out. This adds strength, as well as "surface tension", so that router bits don't sink in as easily when joining end pieces, backing, or making corrections. I use 50% elmer's glue and 50% water to seal, and then Bondo to fill (as it sticks nicely to the glue)

As for the time premium - I would only say that you pay a time premium where it's actually possible to make the shape in some other way. The only other way that I could make this shape with available tools, is to stack the material, laminate it, and hog out a solid laminated "billet" on a CNC machine. That's one option, but it's actually more difficult than than the glued sections. Plus, this is at least somewhat "DIY", where that is not so much. (although I do have the option to do it that way, but I wanted to prove that this could be done - the sections can be sourced cheaply enough to make it worth while)

Still need to get those other pics up. I will show more of the assembly technique.
 

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Discussion Starter · #13 ·
OK, point taken. But what I was trying to say, is that any depth that I add to the speaker would be the amount that I sink it. So the front face would be in exactly the same place. Speaking in relative terms, I shouldn't really be losing anything significant in doing so, other than whatever I have already been forced to compromise. (yes, I'm well aware that a wall mount speaker is not ideal, but it's what I'm forced to work with)
 
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