Bum bags don't have the greatest reputation when it comes to aesthetics. Instructables user mikeasaurus attempted to make them more useful by building in a speaker.
You don't need much to make this project happen:
- One bum bag (or, as our US counterparts would have it, one "fanny pack")
- Two portable speaker amps
- One electronic projection enclosure box
- A drill, soldering iron, scissors and black paint
Once you've got everything you just need to take apart the speakers, put them back together in their new enclosure, and attach them to the bum bag.
Fanny pack boombox [Instructables]