Ammo Box Speakers

This instructable will demonstrate how to turn a .50 caliber ammunition box into a sweet set of speakers that can be used with your mp3 player, laptop, or any other portable device.

This set of speakers is rugged, compact, easy to take on the go, and LOUD!  The whole project will cost about $50.00 usd. and can be completed in an afternoon.

Most of these materials can be purchased locally, but I chose to get some of the items online to cut down on costs.

Heres what you need:

1.  One .50 caliber ammo box- http://www.joesarmynavyonline.com/servlet/Detail?no=5984
2.  Two 4" speakers- http://www.amazon.com/Pyle-PL42BL-4-Inch-Two-Way-Speakers/dp/B000230LBI/ref=sr_1_2?ie=UTF8&qid=1291250695&sr=8-2
3.  2 sets of speaker wires- these will come with your speakers typically
4.  12 volt amplifier-http://www.dealextreme.com/details.dx/sku.34406
5.  3.5mm panel mount plug- http://www.radioshack.com/product/index.jsp?productId=2062450
6.  12 volt illuminated toggle switch- http:// http://www.radioshack.com/product/index.jsp?productId=206249312
7.  Computer power supply- a broken one is ok for this, as you will just be using the plug and cord.
8.  Egg carton foam- I had this piece of foam from some type of packaging.
9.  1 3/4" desk grommet- these can be found in the hardware store or office supply store.
10.  12 volt power supply- this is the kind of power supply that a laptop would use.
11.  Two 4" computer fan grates.
12.  3.5mm male audio to rca audio
13.  3.5mm male to 3.5mm male audio cable
14.  cheap little tripod from the dollar store
15.  various hardware.

You are definitely going to have to wear safety glasses for this project as there are metal bits and solder flying all over the place.  I would also suggest wearing hearing protection because when you get ready to cut the ammo box, it may be the loudest thing ever heard by human ears.

Grab your power supply and remove the lid to expose the guts of the unit, this should be about 4 screws on the outside of the case depending on your model of power supply.  

Next remove the screws that hold the actual plastic plug in place, and carefully pull the plug out and snip the three wires that are attached to it. set the rest of the power supply off to the side. you will not be needing this for any other parts.

Next we are going to mark the ammo box for hole placement. This is probably the most time-consuming part of the whole process, take your time here and do this part right, and everything else will fall into place.

These are the holes that will be cut into the box
1.  2 speaker holes
2.  Bass tube
3. Toggle switch
4.  4 holes for mounting the speakers
5. Hole for the panel mount audio jack
6.  4 holes for mounting the amp
7.  hole for the power plug
8  2 holes for mounting power plug

The dimensions of these boxes vary slightly, so I am going to show you an easy way to do this that will not really require me to give exact dimensions as to where to cut.

I have detailed this part of the process in each following photo, to be as clear as possible.

To cut these holes you will need:
A drill bit 3/8" or larger in diameter
jigsaw with metal blade
round metal file
piece of scrap wood

The first thing is to put on your safety glasses so that you do not lose an eye. You need to cut a piece of scrap wood just long enough to fit in between the sides of the box (see photo). This will keep the metal from vibrating violently during the cutting process.

In this step we will be cutting the holes for the electrical plug, audio jack and the screw holes for the speakers as well as the amp.

for this step you will need:  Jigsaw with metal blade, drill with various sized bits, and a round file, I also used a deburring tool in this step.

The little dollar store tripod will be cut up and used for the standoffs for the speaker covers in this step.  This could be substituted by any tubular material of a similar diameter (1/4" ish).

For this step you will need a phillips screwdriver and a pipe cutter.

In this step we will be mounting the speakers to the ammo box. Before you set your speakers in place, go ahead and mount the wires to the back.  Automotive speakers always come with the speaker wires in the box, and they are typically keyed meaning that the wires can only go on one way, there is a small plug and a large plug with corresponding small and large fittings. So go ahead and attach the wires and then slide the speakers into place with the wires laying inside the box for now.

In this step we will be wiring up the plug that brings the electricity into the box from the outside. this step is pretty straightforward.  Just take your time and use caution with all of the tools involved. and make sure nothing is plugged in while you are working on it.

for this step you will need:  wire strippers, phillips screwdriver, soldering gun, solder, flux, helping hands,  and safety glasses.

In this step you will be wiring and mounting the toggle switch to operate the box.  You need the same tools as the last step so let's get to it.

In this step we will be wiring up the audio jack and installing it into the box. this step is very simple and is the last of the soldering required for this project.

Ok , all of the hard work is done, it is easy rolling from here on in.  In this step you are just going to be plugging the necessary wires into the amp.

In this step you will be attaching the grommet that acts as the bass tube, as well as the sound dampening foam, which will help the box not sound like a metal box.

I went and bout some self adhesive feet for the bottom of the box not only does it help with vibration but it makes it not mar the surface that it is sitting on.

ok so you are done!!!!! at this point you can just go ahead and tinker around with your bass levels and volume to get the desired sound you like. Just as a note the box sounds radically different with the lid open or closed. so when you are making your adjustments be sure to close the lid so that you can hear the full effect.  I hope you enjoyed the instructable and feel free to hit me with any comments or questions.