I got inspired by the Kit of No Parts: http://web.media.mit.edu/~plusea/

And decided it was high time to make a 3D printable speaker prototype. I turned the basic design of a speaker upside down and put the coil on the bottom to simplify construction. (With magnets being as strong as they are lately this is probably fine.)

You'll need a strong, light magnet (the little cube ones from makerbot are probably ideal) paper, and magnet wire.

Once my ToM is constructed, I'll edit in my experimental results, patterns for paper, updates, etc.

Wrap the magnet wire around the inner "spool" shape a good number of times (probably 20 or more for best results, although I have no test data yet) and secure with glue or knots in the wire so it doesn't unwrap on you. Poke the wires out the bottom where they'll become your leads.

Glue the magnet to the center of a paper circle (black construction paper will probably look quite legit) and glue to the speaker.

Important: make sure the magnet is centered above the coil as well as possible. Also important but less crucial probably: make tabs for the paper circle so that you're not gluing the whole rim, just the edges. This creates the "diaphragm" of the speaker.

Plug into an amplifier, play sounds, hopefully.