Information on sound and Alan Blumlein's stereophonic recording system. 

Before 1931 sound was only recorded mono-channel, which created the unnatural effect of sound always coming from only one direction. A discontented Alan Blumlein, a former President, solved this with what he called binaural, but what we know as stereophonic recording. 

Blumlein's concept of recording through two channels, using two microphones placed around the source and played back through two speakers placed approximately where the microphones had been, was simple yet it radically changed the quality of sound reproduction. Sound no longer emanates from a point source, but instead seems to be spread out as it naturally would be. Thus, some of the ambience of the recording studio is recreated.