wedge style box

So I am building a wedge syle box like style 2 pictured in the volume calc guid for 2-8's. Only the short flat height 2 is the top of the box and the long height 1 is the bottom.  It will be about 4" at the top and 8" at the bottom. My question is, for the 3/4" mdf I will be using, what is the best/strongest way to attach it all together? Sandwich the top and bottom pieces between the side and divider piece or have the sides overlap the top,bottom, and back? For 8's its probably not as crucial but I figured it would be a good question to ask for least amount of flex. I hope it makes sense what I'm asking for. If I knew how to attach a quick drawing I would. any help would be great, thanks.

I would have the top, bottom, front, and back overlap the 2 sides. This way the 2 side boards provide support for the rest of the box. If you put the sides as "caps" its not as strong.

In What is a Proper Sub Box, forbidden wrote, "When I build my sub boxes, I build them all the same way. There are some exceptions, like a fibreglass spare tire well enclosure but for mdf, they are built the same way. All of my past installers also now build their boxes the same way. I build my boxes as a sandwich. This means that it is the easiest way to construct a box from top to bottom. All cuts can be made at the same time for width, then cut as needed for length. I will cut my top and bottom first, then I will cut all the inner pieces, the front, back, sides and dividers (if necessary) to width. Then I will cut the inner pieces to length. This way there is little changing of the fence on the tablesaw and one piece is not 1/16" shorter than the other side may be."

This is a very informative paper if you haven't read it yet.

The methodology Rob describes is indicative of shop work where numerous enclosures are built...sometimes on a very short time leash.  In the case of the DIYer with only one project in the works, and especially in any case where a box is to be built in the wedge shape and having a slanted side, the methodology of the build is customized to that particular box.  You always consider ease of measuring and cutting the wood and you must also consider how the box will be assembled during the important clamping phase as the glue sets up.

Two ends of MDF that meet to form a corner will have the same strength if overlapped in either direction.  The quality of the glue that is used and the accuracy of the cuts are what is important.  But in the case where you will have to clamp a wedge style box, the need to clamp will tell you how to cut the pieces.  You don't want to get stuck having to rig up a clamping device to press an angled piece against a flat piece, so you wouldn't want to have to clamp the slanted front to the straight back.  With your design, you would want to bar clamp the top to the bottom.  That means that the top and bottom overlap the sides, as daburrrninator advised.  But when you build a customized wedge shape that has the slanted side on top to fit the vehicle best, the overlapping pieces should be the sides.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

I love the lip I built into my current box. My box sits behind the rear seat of my F250, so it took out most of my behind the seat storage. The box in my 89 was the same rough dimensions, but nothing would sit on top of it when I moved the seat. This box, I built the sides, back, bottom and top first. Reinforced it some and then screwed the board with the sub holes cut out to it. I made the facing board 4" taller than it needed to be. This lip holds my jacket and winch cable in place even when the seat is flipped forward.

When I build my next box for this truck, it will have a lip, but only about 2" tall this time.

Very good info. I did not find any good section like that in my searching. I'm still waiting on my subs from ed before the fun begins. I could do all but the face board I believe which is the trickiest part of cutting and clamping/screwing as mentioned. I'm excited. I haven't built a box since high school, and thats a while ago. thanks for the help and info again.