Perception of sound: Binaural fusion

This is the brain's ability to fuse two similar signals that reach the ears into one single signal; the new signal is, so-to-say, a creation of the brain's which doesn't exist in reality. Let's consider a xylophone for example. If we play a melody and record it on one track and straight after play the same melody but with a few variations, and we record it onto another track, and thereafter play the two recorded melodies sending one through the left channel and the other through the right, what results is a third melodic line derived from the fusion of the previous two but which in fact doesn't exist. This is one of the secrets of the magic of music: the single instruments execute single melodies and if we pay attention we can isolate them and listen to them individually even if all the instruments are playing simultaneously. But if we step from a practical level to an abstract plane we can say that it is in that precise moment that we manage to perceive that which doesn't exist, the combination of all the sounds that creates a harmony: and it is in that very moment that music is born!