How can songs produce softer sounds in one earphone and louder on the other simultaneously?

Question

Sometimes I hear songs where it seems the audio is ‘advancing’ and growing louder from one side to the other. How is it possible?

In: Technology

Answer 1

In most audio files there just are two tracks, one for the left ear and one for the right. If they match, the sound is “ordinary”. But they can be altered separately for the stereo effect.