A Simple Loudspeaker Which Students Can Build and Take Home

We have developed an inexpensive electrodynamic speaker which students can build and take home. The design uses a plastic drinking cup as a base, the tight-fitting lid as the cone, and a drinking straw as a support for the voice coil. The permanent magnet fits inside the cup. Steel washers and a bolt are used to produce a field configuration similar to a commercial speaker. The speaker produces a loud and clear sound when connected to a home audio system. It has been used with students at the middle, high-school, and college level.