The next revolution in the development of headphones occurred after the Second World War and was associated with the emergence of Stereophonics and the widespread industrial introduction of this technology.
The EMI Recording Studio was a pioneer of stereo recordings in 1957, and the first commercial stereo headphones were created a year later by musician and show business manager John Coss, founder of Koss Corporation.
John Koss heard about the "binaural recording tape" from a friend and was delighted to see the benefits of stereo sound through a pair of military-style headphones. He decided to allow everyone to enjoy the stereo sound and as a result, developed a whole "private music listening system" - the Koss Model 390 electric player. The system included a phonograph, a loudspeaker and a headphone jack in one small package. The only problem was that at that time, there were no headphones on sale that were compatible with its new electric player.
All the headphones were then used either for communications or military aviation. Koss discussed the problem with the audio engineer and they quickly made a hand-made pair of headphones that became the prototype of modern devices. "These headphones sounded great," recalls Koss. The design consisted of two brown plastic cups that contained three-inch speakers and were protected by lightweight perforated caps. Both cups were connected by a bent metal bar. This is how Koss SP-3 headphones appeared.
"This product was extraordinary," recalls Koss. Music lovers quickly appreciated it for its excellent stereo sound, which brought the quality of music closer to the concert hall. The design was highly appreciated during the debut of the Hi-Fi trade show in Milwaukee in 1958 and was very quickly copied by other manufacturers who standardized the design of headphones around the world in the next few years.
An interesting addition to this story was Friedrich Kittler's study of media theory that, although John Coss created the first real stereo headphones, the first people to use stereo sound in headphones were Luftwaffe pilots during the Second World War.
In his book "Gramophone, Film, Typewriter" Kittler describes an innovative radar system used by the German Air Force during the Second World War, which allowed bomber pilots to use headphones to reach their destination and drop bombs accurately without even seeing their targets visually:
The radionuclides generated from the coast opposite Britain ... formed the sides of an invisible triangle, the top of which was just above the target city. The right transmitter generated and sent a continuous series of Morse code dashes to the pilot's right earpiece, while the left transmitter generated point signals that the pilot heard in his left earpiece. As a result, any deviation from the course led to a very melodic ping-pong telephony.
When the pilot reached his goal, two radio signals merged into one continuous sound. As Kittler writes, "historically, it was German pilots who became the first users of telephone stereophony, which is now used everywhere.
The above headphone designs are only selected fragments in the history of personal audio development. It is quite possible that the first devices were created even earlier, and for sure we should be grateful to a set of unknown before inventors for their contribution to the development of modern headphones.
It is these products that allow us, for example, to protect ourselves from the roar of jet engines in an airplane and enjoy music at this time, to playgroup computer games over the Internet, coordinating joint actions through headsets, or just walk down the street listening to personal audio players.