Development of Coated Tape and the Magnetophon in Germany in the 1920s thru 1950s

Altho Oberlin Smith proposed magnetic recording on a wire or a tape, possibly a coated non-magnetic medium, in 1888, almost all of the magnetic recorders from 1900 to 1946 used a steel wire or tape as the medium. But a steel medium always had insurmountable problems: it is expensive, heavy, hard to handle, and hard to splice. Then in 1928 the Austrian Fritz Pfleumer conceived a method for applying a magnetizable coating to a non-magnetic base. Thus was the beginning of the modern "tape" and "tape recorder", developed in Germany over the period 1930...1942. The 1940s Magnetophon is the basis for the world-wide development of magnetic tape and tape recorders beginning in the mid-1940s.

The Magnetophon story is told several places, including on Wikipedia. Friedrich Engel has told the story of "The Introduction of the Magnetophon", with illustrations, in "Magnetic Recording, The First 100 Years", edited by Daniel, Mee, and Clark (IEEE Press, 1999).

Friedrich Engel and Peter Hammar have written another detailed and authoritative English-language paper on the Development of Coated Tape and the Magnetophon in Germany in the 1930s thru 1950s.

The technical details of the Magnetophon were given by
Drenner, in 1947, and more technical details are in the original German-language papers..

It is well-known that ac bias, one of the essential ingredients of high-fidelity magnetic tape recording, was originally discovered by Carlson and Carpenter in the US in 1921, then forgotten, then re-discovered independently by three different inventors, including Weber and Braunmuehl in Germany, around 1938...1941. We have recently found a fourth discovery of ac bias, by Wooldridge in the US around 1938, at Bell Telephone Laboratories (BTL). Unfortunately, BTL management thought that a high-quality magnetic recorder would reduce the use of the telephone, so they delayed publication of Wooldridge's paper until 1946, and even then "hid" the mention of ac bias in a footnote.

Those who read German should enjoy Friedrich Engel's "Zeitschichten: Magnetbandtechnik als Kulturträger. Erfinder-Biographien und Erfindungen. Zweite Ausgabe 2010. Chronologie der Magnetbandtechnik und ... Fernseh-, Musik-, Film- und Videoproduktion." 

J. McKnight, 2011-09-12
AES - Audio Engineering Society