How many channels are in stereo?

How many channels are in stereo?

The channels are generally divided into left channel, right channel and stereo.

Stereo, as the name suggests, refers to sound with a three-dimensional effect.

First, it's a geometric concept, referring to something that occupies a place in three-dimensional space. Because the sound source has a definite spatial position, the sound has a definite direction source, and people's hearing has the ability to distinguish the position of the sound source. Especially when there are multiple sound sources producing sound at the same time, people can perceive the spatial distribution of each sound source by hearing. In this sense, all sounds produced in nature are stereophonic. Such as thunder, trains, guns and so on.

When we directly hear the sounds in these three-dimensional spaces, in addition to the loudness, tone and timbre of the sounds, we can also feel their orientation and layers. This kind of sound directly heard by people with spatial distribution characteristics such as azimuth level is called stereo in nature.

Secondly, the sounds produced in nature are stereo, but if we record, amplify, etc. and reproduce these stereos, all the sounds are released from one speaker, and the reproduced sound (compared to the original sound source) is not Stereoscopic. At this time, since various sounds are emitted from the same speaker, the original sense of space (especially the sense of spatial distribution of the sound group) also disappears. This playback is claimed to be mono.

If the entire system from recording to playback can restore the original sense of space to a certain extent (it is impossible to restore it completely), then this playback sound with spatial distribution characteristics such as azimuth levels to a certain extent is called sound technology in audio technology stereo.