Stereobelt

The Stereobelt was the first portable personal stereo audio cassette player. It was invented by the German-Brazilian Andreas Pavel. The Stereobelt was the ancestor of the Walkman and modern-day personal audio devices such as the Zune and the iPod.
A former television executive and book editor, Pavel invented the Stereobelt to "add a soundtrack to real life" by allowing the user to play high-fidelity music through headphones while participating in daily activities.