The box is made from this single 1/2" thick walnut board. I cut it to 8" in width at the table saw. 

I put my 3/4" dado stack in the table saw and raise it to the height of the thickness of this sample piece of leather.   

After running a sample board over the blade, I check to make sure the depth is deep enough. It was so I moved on.

I set the fence to 2" and run the walnut board over the blade. I rotate the board and run the other edge against the fence, creating a channel in the middle of the board. I continued to move the fence over 3/4" (2 3/4" was the next fence setting) until the center of the board was removed.

Tested the fit of the leather one more time to make sure it was snug.

The top/bottom panels are cut oversize to 13 3/4". The final size of the top and bottom panels are 13 1/2".

I also cut the side panels oversize to 6 3/4", making the final size 6 1/2".

With a 1/2" dado stack in the saw, and the fence set 1/2" away from the blade, I cut a 1/4" deep groove for the front speaker panel.

I also put this 1/2" groove in side panels.

With all of the grooves cut, I put my regular blade back in and tilt it to 45 degrees to cut the miters. I cut the miter on one side of the piece.

Then I mark 6 1/2" on the other side and make the cut.

Without moving the piece, I move my stop block up against the piece to ensure the second piece will be the same exact length. I push the second piece up against the stop block and make the cut.

With the pieces back to back, you can tell they came out the same exact size.

I used the same method for the top and bottom panels, cutting them to 13 1/2" in length.

Over at the table saw I cut the front panel out of 3/4" plywood.

I make some center lines for the 4" hole saw to cut holes for the speakers.

I start the cut on one side of the board and go down about half way, flip the board over and remove the rest of the waste. This will prevent any tear out from happening on the plywood panel.

To hide the plywood, I applied a couple layers of speaker grill cloth. I use Super 77 spray adhesive to glue it to the plywood.

This is me applying the second layer.

To mount the speakers to the front panel, I used 1/2" brass screws.

Time for glue up! I put some glue one the miters and assembled the box.

With the tape holding the box together, I added some clamps to bring everything back to square.

Miter joints are weak without any reinforcement. To reinforce the miter, I cut four pieces of 3/4" thick scrap to 4" long.

I put wood glue and CA glue on 2 sides of the scrap pieces.

I set them back 3/4" from the edge of the box and held them in place for about 30 seconds. This gave the CA glue enough time to setup so no clamps were needed.

Next it was back to the 3/4" plywood to cut a piece for the back panel.

I cut a 1" hole in the back panel for the power cable to the amplifier.

Instead of screwing the back panel on, I opted to use magnets. These are 1/4" round, 1/8" thick magnets. I glued them to the 4 scrap posts I glued in earlier.

Oh, the door gets magnets too!

To make the back panel look good, I put 1 layer of the speaker cloth on it using the Super 77 spray adhesive.

I found this pretty cool metal tag on Etsy a while back so I decided to add it to this box. I adds a little flair. I simply attached it using brass screws.

Next up I tackled the leather. I used 3oz - 4oz  veg tanned cow hide for this project, but would likely go thinner for my next box. 

I dyed it using a mahogany alcohol based dye from Fiebings. I applied the dye using a brush and applied a total of 2 coats.

Before applying the leather I cleaned the surfaces of the box with a hand plane. If you don't have a hand plane you could of course use sand paper.

For areas I couldn't get with my hand plane, I opted to use sand paper.

I waxed the leather using Fiebings carnauba creme wax with a cotton wrag.

For the box, I brushed on 2 coats of SealCoat shellac straight out of the can.

24 hours later I sanded the box with 220 grit sandpaper and then put a couple more coats on using a cotton cloth to ensure the finish was smooth and run free.

To apply the leather I simply used wood glue. Any wood glue will work and it sets up fast, so you don't have too much time to move it around.

I made a scrap piece of wood thats the same width as the leather to use as a caul for clamping.

This is the bluetooth amplifier I used but I can't recommend buying it. I've tried 2 of these and they both have insane amounts of feedback that I could not get rid of. It's not an issue if you are listening to something at a decent volume, but if you have it low or paused, the feedback is really annoying. I will be researching to find a better alternative.

To hold the amp in place, I used hot glue. This will allow me to remove the amp if I need to (which if you read the comment above, I will).