I bought a set of super cheap USB powered computer speakers on sale for $4 at my local grocery store a while back. I figured for $4, I couldn't really go wrong. They ended up being underpowered and just all around not great. So I thought with a few slight modifications (new amplifier, internal battery, etc.) I could turn them into a half decent set of travel speakers. Since they were so cheap to begin with, I'm not too worried if they get damaged/destroyed, so they're ideal little speakers to bring on camping trips and the like.
-Old computer speakers
-Female 3.5mm jack
-Replacement amplifier (Optional. You can reuse the original easily, I just wanted a little more power/quality)
-Battery (I used a 1200mAh LiPo I had lying around)
-Charger for battery
-Misc hardware (Depends on your exact speakers)
-Soldering iron and solder
-Heat shrink tubing or electrical tape
-Screwdriver (if your speakers are screwed together)
-Tweezers (not necessary, but very handy to get into tight spaces)
-Hot glue gun
*Before I begin, I apologize for the lack of pictures from some steps. I got a little too into making it and forgot to take pictures of some of the steps!
I added a video of it playing. Not crazy powerful, but pretty decent for what it is :)