Here are some things about binaural effects and stereo sound:

Eyes are often used to determine the position of objects, but if you cover your eyes, you can also roughly determine the position of the speaker. Why? This is because people have two ears, the distance from the sound source to the two ears is generally different, and the time and intensity of sound reaching the two ears are also different. These differences are an important basis for us to judge the direction of sound source with our ears, that is, binaural effect. It is because of the binaural effect that people can accurately judge the direction of sound, so the sound we hear is three-dimensional. But if the sound on the stage is amplified and played with only one microphone, what we hear is no longer stereo. In order to reproduce stereo sound on the stage and make us feel immersive, we can put the microphone in different positions on the left and right (equivalent to human ears), amplify two sound signals with two lines respectively, and then play them through the left and right speakers. In this way, we feel that different sounds are coming from different positions, which is what we usually call stereo.