Broken speakers are pretty but useless, media cabinets are ugly but useful, a synergistic melding of the two objects was all but inevitable.
All you'll need to do this project is:
1. One (or two) old free standing speakers, the bigger the better. Preferably in good aesthetic condition, preferably broken, and preferably free (I gave myself a $20 spending limit for mine).
2. A hand saw
3. Some hinges
4. A claw hammer or crowbar
5. Some paint
6. Planks of wood (to make shelves)
7. Screwdriver or a power drill
8. Roughly 2.5 liters of pure, unadulterated gumption. Feel free to replace with true grit.
I also used a rotary tool, but I'm sure you could pull this project off without one.
Step 1: Disassembly
In order to keep the actual speakers (which are usually really fragile) out of harm's way while doing this project, you first need to get them out of the speaker cabinet. Typically this will just require you to unscrew a few phillips screws, then yank on some wires until the speaker breaks free. This is what we in the business call "the easy step".
Step 2: Disassembly (cont)
All speakers have enormous magnets stuck to the back of them that would absolutely wreak havoc on any DVDs, cds, or video games that you put in your cabinet, so those have gotta go (in the first picture, the magnets are the two black rings at the top of the speaker cone, though most speakers only have 1 magnet on them).
Fortunately, these are usually only held on by some small metal pins and a lot of glue (as you can see in the second photo), so they're pretty easy to get off. Just take a crowbar or a chisel and hammer it a ways down into the seam between the speaker cone and the magnets, then pull it out and repeat that action around the full circle of the magnet until it eventually pops off (once you get the hang of it each one should only take you 30 seconds or so, unless the speakers are really tough).
Once you've removed the magnets from all of your speakers, wallow in the delicious scent of self satisfaction before returning to work. It's now time to focus our work on the cabinet.
Step 3: Cutting a Door
There's a million (well, maybe not a million, but at least 7) different ways to cut a door out of a speaker box, so you don't have to do this the way I did. That said, one thing that you must do when working on this step is make sure that the door you cut out of your cabinet does not touch the ground. You want it to cut through the front face of the speaker box so that the door won't drag across the foor when you open and close it, but at the same time you want the cut to be inconspicuous enough that your end product will come out looking like a media cabinet disguised as a speaker, not a former speaker that you clearly butchered the bejesus out of for seemingly no reason. This can be a little tricky, but with some patience anyone should be able to pull it off.
First measure out and mark the lines of your cuts, then make those cuts. To make the awkward cuts on the side of my speaker box I first took a rotary tool and cut a groove into the lines where I was going to make my cuts (pictured), then took a hand saw and finished those cuts. You could probably use a jigsaw or a circular saw to accomplish this same end, but I'm not very good with those tools, so I took the old fashioned route.
Step 4: Internal Clean Up
Once you make your cuts, your speaker should be in two clean cut pieces as is pictured here (yours probably won't look nearly as good as mine, but whose fault is that? Hmm??)
Speaker boxes are held together with goopy epoxy-like glues and their insides are never intended to be viewed by anyone, so you'll probably find a lot of glue globs and what not stuck to the box's inner side walls. Take a chisel or knife or whatever and scrape that stuff off, and get rid of any other stuff you might find in there while you're at it (for structural stability purposes, a lot of speakers have little wooden blocks glued into their corners on the inside).
If any chunks of wood have come out with the glue globs, or if you had a missed cut or two when you were slicing out your door, fill in those errors with either some wood filler or some epoxy putty (I recommend J&B Waterweld, as it's the best stuff on the market). After that, sand the inside of your box until you're pleased with its overall smoothness. For the record, I was chasing after Billy Dee Williams level smoothness, so I had to sand mine for a LONG time.
Step 5: Paint 'n Stuff
If you want to have shelves in your cabinet, secure those into place wherever you want them. The side walls on speakers are usually too thin to effectively use wood screws on, so if you're going to hold your speakers up with L brackets you'll need to either use nuts and bolts or some epoxy putty to hold them in place (I went with the epoxy putty, as you can see from the white globs beneath each of my shelves). Then again, you could just run some wood screws from the outside of the speaker box directly into the sides of your shelves, but I didn't think of that while I was doing the project, so I went with plan A (which, admittedly, probably should have been plan B).
Once everything structural is in place, lay on a couple coats of paint (unless you want to showcase the gorgeous particle board on the inside of your cabinet). I won't tell you how to properly administer paint, as anyone who doesn't know how to do that almost certainly wouldn't know how to read either.
Step 6: Hinges and Sexiness
Get out your hinges and carefully affix those things to your speaker box and speaker's front panel, so that it can swing in a door-like fashion. This door-like swinging object will henceforth function as your door. It might also be a good idea to attach some sort of handle to the front of your cabinet, so that opening it won't require 4 inch long fingernails.
Once that's done, you're free to stand your new kickass media cabinet up and see how it works. If you did everything correctly, your new media stand should be the envy of every Tom, Dick, and Harry within a 10 mile radius of your living room (though I won't be envious at all, as I already have my own speaker media cabinet... also, my name is not Tom, Dick, or Harry).
I'll hopefully be porting a lot of these projects of mine over to instructables in the coming weeks, but not all of them, so if you want to see some of my other stuff please check out: My Drivelicious Blog