Alan Blumlein
Invented stereo sound, helped create television and radar, and died testing his own equipment at 38
Alan Blumlein was a late reader. His school reports were poor until he was about 12, though he had been mending household electrics since he was seven and had already decided to be an engineer. He took a first-class degree at City and Guilds College, London, and by his mid twenties had designed telephone equipment that saved the Post Office large sums and earned him a prize.
In 1929 he joined the Columbia Graphophone Company, later part of EMI, to work on gramophone recording. Sitting in a cinema with his wife in 1931, annoyed that the voice of an actor came from one loudspeaker while the actor stood on the other side of the screen, he worked out how to record sound with two channels so that it seemed to come from the right place. His stereo patent of 1931 described almost everything used in stereo recording and film sound for the next fifty years. EMI could see no market for it.
He then turned to television, and led the design of the electronic 405-line system with which the BBC began the world's first regular high-definition service in 1936. When war came he moved to radar, and was central to the development of H2S, which let bombers see the ground through cloud.
On 7 June 1942 the Halifax bomber carrying an H2S prototype crashed in the Wye Valley on a test flight, killing everyone on board. His death was kept secret for years.