Stereophonic sound system, sound recording and reproduction technology that employs two or more independent channels of information for a more multi-directional sound. Two microphones are strategically placed relative to the sound source during two-channel stereo recording, with both recording concurrently. The two recorded channels will be comparable, but they will have different arrival times and sound pressure levels. This is in order to create a feeling of recording-hall acoustics. In 1881, Clément Ader demonstrated the first two-channel audio system in Paris, using a series of telephone transmitters connected from the Paris Opera stage to a suite of rooms at the Paris Electrical Exhibition, where listeners could hear a live transmission of performances through receivers for each ear.

This two-channel telephonic method was commercialized as the Théâtrophone (the theater phone) in France from 1890 to 1932, and as the Electrophone in England from 1895 to 1925. In the 1950s, two-track stereophonic tape for the home became popular, and in 1958, the stereophonic phonograph record, with two distinct channels of information recorded in a single groove, was introduced. Quadraphonic sound systems, which use four independent channels of information for even greater realism, became commercially accessible in the early 1970s, eventually leading to “surround-sound” systems.

Time difference in a stereophonic recording of a car going past

https://en.wikipedia.org/wiki/File:Carsoundstereoshift.png

Citations 

Wikipedia Contributors. “Stereophonic Sound.” Wikipedia, Wikimedia Foundation, 3 Nov. 2019, en.wikipedia.org/wiki/Stereophonic_sound.  

The Editors of Encyclopaedia Britannica. “Stereophonic Sound System.” Encyclopedia Britannica, 10 Feb. 2011, www.britannica.com/technology/stereophonic-sound-system. 

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