Gear

Polyethelene Cup Speaker (With Styrofoam Upgrade)

You must now make your own sizzlebrator with a coil of wire, a business card, a magnet, LEGO bricks and a plastic cup. As high-tech and sleek as it looks, know that it also produces a decent sound. It is, however, rather quiet. If you need a boombox, replace the cup with a styrofoam plate. […]

Homebrewspeakerlego
You must now make your own sizzlebrator with a coil of wire, a business card, a magnet, LEGO bricks and a plastic cup.

As high-tech and sleek as it looks, know that it also produces a decent sound. It is, however, rather quiet. If you need a boombox, replace the cup with a styrofoam plate.

How to make a speaker [Via MAKE]