As with most of my projects, I'll have an idea on what I want to build but no clear destination for the outcome. I knew I wanted another 2 x 12 speaker cabinet, or maybe 2 x 10 or... something? This build ultimately became a 2 x 12 open-back cabinet. Although I hadn't originally planned on this as an Instructable, I felt that I had accumulated enough photos to document how I built this particular cabinet.
Unfortunately, you will find that the final covering of the cabinet wasn't documented. (I am however, planning on a second cabinet that I will focus on the covering.) Once I started with the fabric, I just plugged along as the adhesive didn't provide me with much work-time. Therefore, this Instructable focuses on the building of the actual cabinet.
Step 1: The Cutting of Parts and Rough Assembly.
The overall dimension of the cabinet are 30.125 x 17 x 12.5 and will comfortably fit 2 - 12" speakers. As I didn't have any birch plywood available (which seems to be the popular choice for cabinets), I used maple as both have very similar properties and will provide a good finished product.
This cabinet required;
2 pcs. - 30.125" x 12.5" x .75" maple plywood (top & bottom)
2 pcs. - 15.5" x 12.5" x .75" maple plywood (sides)
1 pc. - 8' 1 x 4 clear pine ripped into .75" strips (internal framing and bracing)
1 pcs. - 15.25" x 28.375" x .5" maple plywood (front baffle)
2 pcs. - 6.5" x 28.375" x .25" maple plywood (back panels)
2 pcs. - (back panels)
8' - 1" x .25" maple plywood strips -or- 6 of the 5 gal. bucket size paints sticks (front frame around the baffle)
Note: There's an old DOS program on the internet called 'Cutlist'. If you input your material size and the sizes of the pieces you need it will help lay them out to minimize waste.
As with every project test fit everything before actually assembling.
In the above pics, I show the assembled sides. The front of the side panel has the .75" piece flush with the front as the baffle will mount behind it, in the next pic the .75" piece is mounted about .5" inset from the back. You will notice that the rear strip has an angle cut on it. In the next step of this Instructable, I jump ahead to show why that is and have provided one of my scribbles to help explain. Next, because the sides will mount inside the edges of the top and bottom, the .75" strips will need to each be 3" smaller but mounted in a similar fashion. Flush in the front, inset .5" in the back and centered on the piece.
The last pic shows the baffle. It has the strips/paint sticks being mounted around the perimeter to keep the grille fabric off of the front of the finished piece, no other reason.
Step 2: The 'jump Ahead' Portion.
Ok, this is why the rear strips as well as the front of both the bottom and top pieces of bracing have an angle cut them, it's so that the baffle can slide into place. Now back to building the cabinet...
Step 3: The Cabinet Assembly.
With the front and rear pieces (the .75" strips) of framing assembled on the top/bottom/side pieces, you have a convenient place to attach your clamps and squares during assembly. I assembled one corner at a time, adding a piece of bracing in each corner (being mindful of the installation requirements of the baffle), glueing and screwing everything that came into contact with another piece of wood and allowing each to dry overnight before moving on to the next corner.
Step 4: Make It Smooth.
After the 4 corners have been assembled, you basically have your cabinet. You're now in the finishing stages.
Because any imperfections in the finished cabinet could potentially transfer through to the finished covering, I filled every void with wood filler. Once dry, I sanded everything then, using a .5" roundover bit on my router (In this instance because that is what the metal cabinet corners I chose required.), routed all of the outside edges. Then, filled and sanded everything again.
Step 5: Prepare for the Hardware and Covering.
At this point you've probably picked out most of your hardware. I cut the appropriate size holes for the handles then painted the interior of the cabinet as well as a little on the outside of the corners to help conceal the seams during covering in case something didn't go quite as planned. I also painted the entire baffle, both front and back.
Because of the handles I chose, I had to install the baffle first. This ultimately means that the cabinet will have to be covered as well as the grille cloth before I could install my handles. Depending on your hardware choice, this may not be necessary.
Step 6: The Covering.
As I admitted, I didn't have much of an opportunity to take pics of the covering process due to the short work-time on the adhesive, but I have included a couple finished pics. One last thing I chose to do while assembling the cabinet was to install an additional piece of wood to help strengthen the top panel where the jack is located as it would be plugged/unplugged fairly often and the additional support would be beneficial.
Because we're at the point where the cabinet is covered and the baffle is installed, it was time to wire the speakers.
I wanted the cabinet to run at 8 ohms so I chose 2 - 16ohm speakers and wired them in parallel. Which, as shown in another one of my scratches, is Speaker A Positive -> Speaker B Positive -> to Tip / Positive on the jack. Then basically the same with the negatives but to the Sleeve / Negative on the jack.
Step 7: Button It Up.
At this point, attach your hardware and you should be done.