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.

Step 1: Materials

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-
2.  Two 4" speakers
3.  2 sets of speaker wires- these will come with your speakers typically
4.  12 volt amplifier-
5.  3.5mm panel mount plug
6.  12 volt illuminated toggle switchhttp://
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.

Step 2: Safety Gear

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.

Step 3: Remove the Plug From the Power Supply

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.

Step 4: Mark the Ammo Box for Hole Placement

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.

Step 5: Cutting the Holes: Speakers and Bass Tube

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.

Step 6: Cutting Holes Part 2: Plug, Audio Jack, and Screws

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.

Step 7: Cut Up the Tripod!

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.

Step 8: Mount the Speakers

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.

Step 9: Attach Wires to Plug

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.

Step 10: Wire and Install Switch

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.

Step 11: Wire Up and Install the Audio Jack.

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.

Step 12: Plug the Amp In

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.

Step 13: Install the Grommet for the Bass Tube As Well As the Foam

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.

Step 14: Install Feet

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.

Step 15: Adjust Your Levels/ Finished

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.

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211 Discussions


Question 13 days ago on Step 1

is the grommet size 1 3/4 or 3/4?


Question 5 months ago on Introduction

Nice project. Is there a rechargeable battery option?


Question 1 year ago

Why the port? What is the benefit of a port versus a non-ported speaker?


1 year ago

2 suggestions, first is getting a $15.00 Bluetooth receiver to connect with your phone instead of hardwire to your music source, normally runs up around 6 hours per charge. Second, use 12volt gel cell instead of the power supply to make it totally portable. I have run this setup for hours for a Christmas parade float music. Use a small 12 volt power supply to recharge the battery as needed.


3 years ago

Question, i am getting little to no audio out of my speakers even with both the amp and phone volume maxed out. Any ideas. Im pretty electronically inept so any and all suggestions are great.

2 replies

Reply 1 year ago

If you've skipped the bass tube then your case may be pressure sealed, which will muffle your speakers badly. Try opening the lid, does that fix it?

You *definitely* don't want to leave it sealed if it is, it's really bad for the speakers. And, y'know, you don't get any sound out of it.


Reply 2 years ago

Check what wattage your speakers can take versus the wattage the amplifier puts out. You may just need to get a different amp that puts out a much higher wattage.


2 years ago

How or what would i have to do in order to install batteries so it is portable


2 years ago

I started my ammo box build with 6" speakers . Any thoughts on 1 speaker i know its too big for two unless i out one on each side any thoughts?


6 years ago on Introduction

Ive had a need for a loud portable durable speaker for a few years and never could find one to buy that satisfied my needs and wasnt outrageously priced. Did a lot of research into making my own before stumbling across some ammo can speaker projects like this one and decided to make my own.

Used a 50 cal ammo can which I applied a butyl sound deadening material to, some kicker 4" speakers, Lepai t-class amp and a 7ah 12vdc sla battery that is most commonly used in home alarm systems with quick connects for a battery tender for recharging. Audio is connected to a 3.5mm plug with my ipod. I also did some subtle customization to keep the military feel with the blacked out nut washer combo and the graphic i made and trimming the speaker grills in flat white.

The 7ah battery is a little overkill since this amp and speaker combo is very loud and efficient. Future mods in the next few weeks will include:

-port tube hidden under the latch
-lighter battery pack (prob a 3ah li-ion)
-speaker feet
-bluetooth connectivity

7 replies

Thought I would come back a few years later to drop an update on this project.

I ultimately ended up ditching the .50 cal ammo can for a .30 cal can which is almost half the depth and almost half the weight. I also ended up changing to a dta-2 amp and a 3.8ah Li-ion battery pack along with bluetooth 3.0

This setup is about a 40% reduction in size and 60% reduction in weight without a significant decrease in sound quality and battery life is still killer.

The bluetooth range is pretty limited mounted inside the box but as long as its close by all is good.

After tons of tinkering and lots of parts swapping I heavily recommend this setup.

Links for components below:


Reply 2 years ago

Love the idea. Question on your .30 cal version. Anything you would change if you did it again? And what were your thoughts on that Amp you used? Thanks!

How did you wire the battery into the amp. I have fried two amps now. I have a switch with an LED in it, From the battery the positive goes to the positive the ground to the ground. I cut the cable supplied with the amp and ran it to the switch directly. The all black wire ran to the ground on the switch, the black and white wire runs to the switched power on the switch itself. Am I missing something here.


Ok. I think I figured it out. I had the wires going to the amp backwards. I checked on a laptop 12 volt power supply with my multimeter and found that the inside of the plug was the "hot" side, and the outside was the ground, which is the opposite of the way I had my power unit wired.


Reply 6 years ago on Introduction

Have you come up with a way of doing internal bluetooth? I've been kicking around that idea for months and cant get around the notion that a bluetooth receiver inside a sealed steel box would have a range of about 14 inches, haha.

I have found lots of simple solutions on bluetooth receivers, some even run off of 12v so they could be wired to the battery... but the range problem still eludes me.


Reply 6 years ago on Introduction

Ive contemplated the idea for my next one as well, and the only solution ive come across is taking a bluetooth reciever apart, finding where its internal antenna is and mounting/ attaching a wire or other antenna to it to run to the outside.

My idea was to make a tiny hole directly next to the speaker and have a tiny wire (antenna) go around the outside of the speaker to hide it inbetween the speaker body and the ammo box. That way you have an external antenna for the reviever thats partly hidden, maybe completely hidden by the speaker mounting body.


Reply 6 years ago on Introduction

I have had the same feeling, especially given that mine is lined in sound deadening material. Ultimately I decided that I will be using:
although I have yet to order it. Small, good battery life, rechargeable, great reviews. The only reason I am even attempting this is because I am porting my box and will be mounting the receiver directly above the port. Hoping this will allow adequate signal transmission but who knows. I will definitely post an update once it is all finished and let you know about the range.


3 years ago

Too Questions: 1. Why not connect the audio input directly to the MP3 input on the amp? 2. Any concern with the internal temp of the ammo box getting too hot and frying the power supply or amp?

1 reply

2 years ago

Hi, I was wondering about that AMP you used in youre project. How did you connect the power supply and the battery to the board? Is there multiple power in connections on it? From what I can see, its just those 4 that are connected dirrectly to the battery.