Stereophonic sound facts for kids

Time difference in a stereophonic recording of a car going past.

Stereophonic sound or, more commonly, stereo, is a method of sound reproduction that creates an illusion of multi-directional audible perspective. This is usually achieved by using two or more independent audio channels through a configuration of two or more loudspeakers (or stereo headphones) in such a way as to create the impression of sound heard from various directions, as in natural hearing. Thus the term "stereophonic" applies to so-called "quadraphonic" and "surround-sound" systems as well as the more common two-channel, two-speaker systems. It is often contrasted with monophonic, or "mono" sound, where audio is heard as coming from one position, often ahead in the sound field (analogous to a visual field). Stereo sound has been in common use since the 1970s in entertainment systems such as broadcast radio, TV, recorded music, internet, computer audio, and cinema.

How stereophonic & duophonic sound systems work. It is an electronic simulation of sound-location-perception. The main diagram shows the situation in nature (simplified drawing), and the inset-image shows the electronic simulation. Notably, such audio systems need more than 1 speaker.

Images for kids

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  Diagram of Clément Ader's théatrophone prototype at the Opera during the World Exhibition in Paris (1881).

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  Bell Labs demonstration of stereo at World's Fair

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  Label and sleeve from Audio Fidelity Records' second stereo demonstration record, ca. 1958.

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  HH Scott Model 350, ca. 1961: the first FM multiplex stereo tuner sold in the US

See also

In Spanish: Sonido estereofónico para niños