A few years ago my sister-in-law bought a house. She gave us a tour, and when we got to the basement I noticed a neat old speaker hanging from the wall that the previous owner had left behind. She let me have it and I threw together a fun little project. I had an old Airport Express that I wasn't using anymore and I thought I'd make an Airport Express speaker.
Now keep in mind that this was several years ago and I was really just dipping my toes into the whole DIY thing. There are a few things that I would do differently now. In fact, I plan to do a revision sometime soon. The upside, though, is that you can't really get much easier than this.
Step 1: What You'll Need
First, you'll need a speaker of some sort, obviously. This one says "High Fidelity", so you know it's freaking amazing. You'll need something to open it up with; probably a screwdriver. You'll probably want to use a soldering iron for some of the connections, though I did not (we'll get to that). If the speaker cabinet only has one speaker in it then you'll want a 3.5mm stereo-to-mono adapter and an audio cable with one end that's got a 3.5mm male plug. If you've got two speakers you'll want to preserve the stereo situation and run an extra cable.
You'll need a power cable to plug into the Airport Express. If you've got a newer model than you've already got one.
Finally, you need an Airport Express. You have other options as well, which I'll cover near the end.
Step 2: Open It Up
Do whatever you have to do to open the speaker cabinet up. Mine had four screws.
Take a look at the situation in there. If it's an old speaker, it's probably pretty simple. You can see in the pictures that there's really just a speaker with some wires soldered to it.
Smarter people than me would probably tell you to to figure out what ohm the speaker is, they may use words like "polarity" or "polar bears", I don't know. Again, this was several years ago, but I'm pretty sure I just tinkered with it until it worked.
So, on to the next step.
Step 3: Connect the Speaker Wire
Ugh — this is embarrassing. I guess I just taped it up with electrical tape. But hey, the speaker has worked like this for several years now, so it must not have been that bad.
So connect the speaker wire to the 3.5mm audio cable. You could solder them and use heat shrink to protect them. That's what I'd do now.
Plug that jack into the stereo-to-mono adapter, and plug that into the Airport Express.
Step 4: "Mount" the Hardware and Test
The indignities continue. I originally used electrical tape to hold the Airport Express in place. While I had it opened I replaced it with painter's tape.
The back panel of the speaker cabinet already had a notch to run a wire out, so that's where I ran the power cable.
Now would be a fantastic time to test this out. I'm not going to cover the configuration of an Airport Express. It's a piece of cake.
Let the sucker power up and try streaming audio to it. If it works, great! If not, try plugging something you know to work into the Airport Express — another speaker, some headphones, whatever. You may have a bad connection, especially if you went the electrical tape route.
So when it's ready to go, close it up.
Step 5: Rock Out
And yes — the name of my Airport Express is, "In Whatever Heinous Realm That It Squats". Deal with it.
Step 6: Some Notes
So, as I mentioned in the beginning, this is extremely simple and could be done a lot better.
First, maybe you don't want to use an Airport Express. I got this bluetooth audio receiver from monoprice a while back. It's okay, though you have to re-pair with it every time.
Or you could do what I plan to do, which is loosely follow this very, very cool instructable and make an Airplay receiver using a Raspberry Pi.
There's also about 100 different, better ways to secure the Airport Express than tape.
Finally, check out the schematic that was inside the speaker. That's how you know this sucker is pretty old.