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The first magnetic audio recording dates from 1898.
The inventor of magnetic recording media is Danish Valdemar Poulsen. He heard himself pronounce the name “Jacob” after recording his voice on a magnetic wire (not yet a tape).
The oldest magnetic recording preserved to date is a speech by Emperor Franz Joseph of Austria broadcasted at the Paris Exposition in 1900. You can listen to it here.
Note that Thomas Edison invented the music disc before Poulsen, but the latter filed a patent for the first answering machine/call recorder in 1899!
Sources :
Rennes academy [fr]
Wikipedia – Magnetic Storage [en]
