D4CDM 1936 Deutschland

D4CDM playing his subharchord.

D4CDM 1936:
Ernst Schreiber, Dresden, D4CDM. It is very likely that D4CDM is identical with Ernst Schreiber, the inventor of the Subharchord, an electronic key board instrument, developed mainly for film in Eastern Germany in the 1950th at the "Labor für Akustisch-musikalische Grenzprobleme". Schreiber first became a high-frequency engineer and worked for the Loewe radio company in Berlin Steglitz. As an avid organ player he later tried to combine hobby (he played regularly at the organ in the church of his home congregation in Pankow) and profession. He first developed the "Toccata organ" and later the Subharchord, see picture of the Ernst Schreiber demonstrating the subharchord in the 1960th and the link to the very interesting website about the subharchord that also describes Schreiber's role as the inventor.
Sources: http://www.subharchord.com

QSL, Photo & Info courtesy of K6EE