1) At least one sheet of 3/4:" thick plywood.

2) Some fabric, I used a thermal emergency blanket, but there is some material that is acctually used for these applications. (http://www.parts-express.com/wizards/searchResults.cfm?srchExt=CAT&srchCat=826&CFID=584439&CFTOKEN=12611822)

3) A terminal plate. Fit for your application. If you have a Dual Voice Coil sub, then wire it up accordingly and run a positive and negative to each terminal. You would need a terminal plate with two terminals, if you had two subs with the same set up, you could use a 4 terminal plate or 2 two terminal plates. (http://www.parts-express.com/wizards/searchResults.cfm?srchExt=CAT&srchCat=417)

4) some 1 1/2" brads/nails

5) Staple gun. For applying material to plywood.

6) 10'-25' roll of high gauge wire(0-4). If you have more amperage, you use a smaller gauge wire. less amperage higher gauge wire. (http://www.caraudiobook.com/car_audio_power_wiring/car_audio_power_wiring.htm)

7) Subwoofer(s)

8) Screws to hold subwoofer on.

9) Jigsaw

10) Recipricating Saw

11) A place to work

 To start the build, first measure your application.  Make adjustments to your box to fit into your trunk, backseat, etc. first thing you will want to do is make a plan.  First take all measurements of how big you want your box.  Make sure you compinsate for the thickness of the wood. For say if you want to make a cube style box 10" high 10"long and 8" wide. you would make your front and back pieces 10"x10" you would then make your top piece 8"x10" but, beware, your bottom and side plates, your bottom plate would only be 6 1/2" by 8 1/2" so that it will fit in under your side, front, and back plates. Don't forget to cut the hole for you subwoofer.  You can do this by finding something round around the house or by getting some string, a pencil, and something to hold your center.  Make sure you make a close measurement on how big your hole needs to be, because anything more or less can either A) not give you anywhere to grab on to or B) the hole is too small for you sub to fit into, so be carful when cutting the hole. Now the side plates would be 6 1/2'' by 10", why? Well remember what I said about compensating for the thickness of the wood. Also in one side plate, DO NOT forget to cut your hole for the terminal. Now that we have these measurements, draw them out on your plywood.  You can use a jigsaw or a recipricating saw to cut these out.  However, you WILL NEED a jigsaw for cutting the circle in your face plate.  After cutting out your pieces now its time to wrap them in material. i go about 3" to 4" over the actual measurement of the piece that way i have enough room to go around the thickness of the wood and have some material to grab on to on the other side.  This is a pretty teedius and time consuming task, try not to get frustrated with the material.  If you need to sit down and take a break for a while, then come back when your ready.  After everything is wrapped up, its time for assembly. The first thing you will want to start with will be the bottom, once you have your bottom ready to go you can put your back and sides on using the brads. at this point, it is best to put the top on first then front later, but you can do it either way. now that you have one piece left to install, go and get your subwoofer.  Hook it up into your terminal and mount it to the faceplate.  Install faceplate to box and your ready to roll.