Telegraphone steel tape recorder (steel tape telephonograph) for magnetic recordings, from the Paris World Exhibition in 1900

In May and June 1900, Valdemar Poulsen experimented with different materials for the wire and cylinders, speeds, and magnetic heads in Mix & Genest’s Berlin laboratories to make magnetic recording technology marketable. To improve volume and intelligibility, this device uses a wide steel band instead of wire. In June 1900, Mix & Genest showcased it at the Paris World Expo, with demonstrations for invited participants and press representatives.