The loudspeaker is a crucial element in the interface between technological devices and their human users. The speaker converts an electrical current into audible sound by application of the phenomenon of electromagnetism. In this project a simple electrodynamic speaker will be built. The design uses a plastic drinking cup as a base, the tight-fitting lid as the speaker cone, and a drinking straw as a support for the voice coil. A permanent magnet fits inside the cup. Steel washers and a bolt are used to produce a magnetic field configuration similar to a commercial speaker. The speaker produces a loud and clear sound when connected to a home audio system.