A Working Pallophotophone - 1922 audio recording method

History in Audio Recording: The only working pallophone in the world(2010), plays back the earliest radio station recordings ever made. It used light bouncing off a tiny mirror to expose a strip of film. A photoelectric cell is used to read the recordings. The film recorded waveforms of sound as tiny black stripes. Demonstration on kodak acetate film. Invented by Charles Hoxie, this lead to the RCA Photophone motion picture system. The machine was built by Russ DeMuth of the GE Global Research Center in