Marc78's version of the 6x9 Rear Speaker Boxes Plan

Here is my version of the rear speaker boxes that Justin78-L-82 posted to corvetteforum.com. I modified the way they mount to the car since I didn't previously have rear speakers, and didn't have the mounting hardware that came with them.  I used Pioneer TS-A6956 'Shallow-Depth Basket' 6x9 speakers I got used off of Ebay for $18.

The final product looks like so:

I started by cutting a template from a cardboard box:

You only need one template since the two sides are just mirror images of each other.

Here are the measurements for these two templates:
PLEASE NOTE: These measurements are not down to the 1/16", and may vary slightly, so please plan to tweak these measurements depending on how meticulous you want to be. There's only an inch or so of space behind my speaker magnet, but depending on the depth of your 6x9's, you may want to try to angle it differently, in which case, most of these measurements will change.

Obviously, the top triangle measurements don't live up to Pythagoreum's Theorem, but you get the idea. Of course, you'll want to trace your own speaker opening and make sure to mark where the screw holes on the speaker are.

Now, after you cut / tweak these templates, trace 'em onto a sheet of 1/4" plywood and break out the jigsaw.  You may want to cut just one set at first just to make sure they fit.  Now pre-drill your speaker screw holes around the speaker opening with a smaller drill bit than the screws you will use to secure the speaker to the box.

Now secure the two pieces together with L-Brackets and very short screws as shown below. (If you are going to carpet the boxes, the screws can stick out a TINY bit, and the carpet will cover them anyway)
Ignore the screws around the speaker hole in the picture... you'll use regular wood screws.

Place the assembled piece into place in the car and you will be able to do the next step through the speaker hole. You will use two more L-Brackets for each box to secure them to the car. One 2 1/2", and the other .. ummm, bigger. (I forgot).

Anyway, while holding your box in place, hold the L-brackets up to the holes in the back of the car and mark where they meet on the box's top piece with a pencil: (You only need to mark one hole)

Unfortunately, you can't see the holes here, but that's about where they are.

Take your box out and screw on end of the L-brackets into the two spots where you marked with a pencil.
So now your box has two L-brackets hanging downward off the top piece.

Lay your carpet fuzzy side down. Place the face with the speaker hole down and measure out and cut the carpet that you need to cover the front and top faces of your box. As you can see in the picture above, I let a little carpet run over the inboard side to make sure I wouldn't see the wood. Now glue on the carpet. I used 3M spray carpet glue.

After the carpet is glued on, make sure the trim and grille fit and take them off. Then drill or poke through your speaker screw holes again to poke through the carpet and make holes for your screws.  Now, assuming you've already run your speaker wire to the back under your carpet, set the box into place in the car and reach through the speaker hole to secure the L-brackets to the back of the car. If you drew your pencil markings correctly, everything should go in nicely.

Now hook up your speaker, and screw it into the pre-drilled holes to secure it.

Put on your trim and grille, repeat on other side, and you're ready to rock 'n roll!

Email me if you have any questions.
mfouchijunk@cox.net