Soundmirror Magnetic Tape Recorder, Model BK-401, 1939-1941

In 1930, a new material--plastic tape coated with magnetic pigment--opened worlds of possibility for sound recording and data storage. Professionals used open-reel magnetic tape recorders to pre-record radio shows; consumer models were used for home recording and music playback. The format was sonically superior to compact cassettes introduced in 1963, but shifted to niche use by the 1980s.