For those of you just joining this thread, I bought two Stereo Integrity BHS-24 high-powered 24" sub drivers. The rated output capacity is over 4000 wpc vs. their original HS-24 driver at just 1500wpc. The stronger magnet also allowed me to build a smaller 10 cubic foot box vs. the 21-ish cubic feet the original driver needed to really "breathe".
With the help of another AVS Forum member and input from Nick at Stereo Integrity, a fully optimized and braced enclosure was designed in CAD to unleash this driver's full capabilities without any compromises. You can see the design HERE
and in subsequent posts in this thread. All internal bracing parts were CNC milled from 13 ply Baltic Birch plywood and the enclosure was milled from 1.5" thick Trupan MDF. The double layer front baffle is at a full 3" thick.
The sub build waited in the wings while I finished the theater room through drywall and was able to clear space to work. Thankfully I have a woodworking neighbor who has a ton of JET parallel clamps I was able to borrow during the glue ups. I used top quality Titebond III glue throughout. Here's the first phase of the build....
I first did a test fit of the matrix bracing in the back piece since I was using the dados in the back to hold the bracing while the glue cured. The one brace around the sub driver was not seating properly which is when I noticed the "dog ears" were accidentally left out of the CAD design.
Here you can see the rounded corners
I added reference lines
and then cut both notches until I had a perfect fit with the other bracing components
On the outside of the back piece I used a square to mark the dado / brace positions. I also made small hash marks where most of the 'meat' of the bracing would be located
Here you can see all the lines and intersecting points drawn on the outside of the back piece
I marked the intersections with my awl
Because of the 1.5" thickness of this Trupan MDF, I used 2.5" exterior deck screws for fixation and a 3/32" drill bit. A drill bit guide would keep all of my holes perpendicular
To verify the bit was large enough to predrill the edge of the Baltic Birch plywood and not split when I inserted the screw, I first predrilled a piece of scrap
then ran the screw all the way in, even though the screw would only penetrate about 1-1.25" deep once it passed through the Trupan MDF.
I used a bit stop with my countersink bit to yield approximately 1 - 1.25" of "purchase" into the matrix bracking through the MDF.
I then drilled and countersunk all the holes. 22 screws to secure the bracing to the back panel in addition to the glue.
Next, I installed the back on the bracing and predrilled the screw locations in the matrix bracing. Not shown is I removed the bracing and fully drilled out all the holes since the drill bit itself was very short and unable to reach the full screw depths I needed with the MDF back in place.
No photos during the glue-up, but on advice from other experts I also shot 18 gauge brad nails through all the bracing intersections from a couple different angles after gluing to really lock it into position.
With both brace glue-ups complete, I turned my focus to attaching the bracing to the back piece with screws. No in-process pictures as I raced to get all the glue applied and everything secured with screws during the limited open time, but installation went well. I could have clamped, but with 22 screws I decided to simply pile on all the baffle material while the glue cured.
Finished the second baffle and added more weight to the total stack.