Well guys construction started last weekend and as of this weekend I've managed to:
1. Cut out and laminate the .75" MDF to 23/32" OSB making the baffles, the sides, and the bottoms.
2. Cut out the two holes for each of the pair of manifolds. Each manifold will consist of two 18s one firing at the other. The opening into the room is roughly 22" x 13 3/4" for each. As you can see from the pics a water pipe prevented my original intention of mounting the woofers in the center of the room in one manifold. I'm sure I could have used an elbow to turn down the water pipe but no thanks, that's just asking for trouble if you ask me.
I have an appointment with a cabinet maker this Monday for him to use his router to cut out the holes for the woofers. I am not really interested in buying a router and circle jig considering I probably will never use it again so I figured that's the best way to go. Unfortunately I was a bit retarded in construction of the first baffle and didn't think to keep the nails out of the way of the circle that needs to be cut. Me and the cabinet guy should have a blast with that one, ha. If we can't get it to work I will just create another baffle.
My plans are to actually build the boxes piece by piece under the crawlspace. With the way the TJI joists are it will be easier that way. I thought about taking two .5" pieces of plywood or OSB and making the TJIs like a normal joist and putting the box up to the bottom like most do but decided against it. It shouldn't be that hard with a buddy and two mechanical jacks that don't sink over time like hydraulics. I planned to mount each baffle board in between my floor joists and then use liquid nails, nails, and screws to fasten the baffles to the inside of the TJI top and bottom pieces (figured on using nails to fasten them in place quickly then drill and screw them into place permanently. I will use the mechanical jacks to give them support on top of what the nails and screws offer till the liquid nails has ample time to set. Once the liquid nails is set and the two baffles are in place the sides and bottom will be fastened on the same way. Finally, I plan to wedge a few 2 x 6s under each manifold to give the hoists a little relief in supporting this weight (estimated to be 120lbs in each enclosure).
Considering the baffles are only 23" wide I'm quite sure there will be no flex at all in this 1.5" total thickness baffle face. Further, the sides and bottom are the same laminated construction so I would think they'd only go to help the rigidity. Hell, if the house falls down (and it's possible from 29 liter of displacement and around 3600 watts, ha ha) these enclosures may be the only thing left.
As you can see the crawlspace is completely conditions which is why I chose this area. The holes in my floors right now have air coming from the crawlspace right now that's the exact same temperature as the interior of my home. Simply a no brainer in back wave containment choice!
Well all this being said feel free to comment. Pics are below.
I simply can't wait to get this up and running. It's funny looking at these four 18" woofers with their rather large surrounds and 30mm xmax and thinking "hmmm, is this a bit on the side of overkill" ha ha.
Once again one can see why I chose this back wave containment area, the entrance is right in my finished garage!
More of my handy dandy redneck body builder clamping system, ha ha. I imagine between the nails and the 150 lbs on top this should be sufficient. Comment if you think otherwise though.
Side shot of the side pieces. The bottoms and baffles were constructed the same way! Construction includes a spread of Titebond II on both the OSB mating face and the MDF mating face. The boards were then laid on top of each other and held as I drove in the 1.5" long nails (quite difficult to hold until the first nail is driven in as the boards want to slide all over the place!!!). After nailing about 30 nails in each the baffles were placed on my garage slab, hammered all over including over the nails again with a sledge hammer, and then placed under the weights.
Just a shot in the crawlspace from the left opening.
The offending water pipe!
The big mess I made!
All cleaned up now! I will be seeking some fancy cover solutions for the two openings in the floor. My mother is an interior decorator and has some ideas but any suggestions from my follow IBers are appreciated! I'm not interested in cold air returns, I want something along the lines of a nice wooden register accept larger to cover the 13" x 22" hole. Each one of the openings yields about 1845 square centimeters which is a bit less then the 2420 which would be required for no effects on sound quality. Judging by my previous posts and Thomas's replies I'm guessing this won't have any noticeable impact on sound quality.