R is short for the English word “right,” indicating the right side. L is short for the English word “left,” indicating the left side. On headphones:
R: right represents the right side, indicating that it should be worn on the right ear.
L: left represents the left side, indicating that it should be worn on the left ear.
Audio devices labeled with L/R are used in stereo systems, where the stereo signal is recorded using special techniques. Therefore, it is necessary to use stereo audio equipment to restore the sound.
In simple terms, if a sound effect of a horse running in front is recorded using dual-channel recording, when you listen to it with the correct L/R positioning, you can hear the horse running from one side to the other. If it doesn’t meet the L/R requirements, you will hear a different effect.
Dual-channel technology is the basis of the so-called 2.1, 4.1, 5.1, 7.1 systems, commonly known as stereo, which provides a certain sense of spatial dimension.