When you play a gramophone music record, you hear an orchestra where no orchestra is seen.
What you experience is the virtual presence, of the INFORMATION of that orchestra.
More than that: you also enter into the space in which the music was recorded.
All of this is possible because of stereo: the sameness of difference; he difference in sameness.
All it takes is two loudspeakers.
The two loudspeakers present the same piece of music.
But each loudspeaker presents a different part, perspective, of the same signal.
And suddenly a virtual space takes place in the space that you are in.
Now imagine the same in your body.
Realise that your right and left body half are to a large degree the same.
Yet, they are also different; just as is the case for a stereo signal.
This puts it at the brink of a yes/no-symmetry-break: optimal switch between dimensions.
Realise that the world that you perceive is not real; it is merely a realisation.
Cells on the surface OF your body relay their response to vibrations to the brain.
The brain makes a composite image out of all those input signals.
Sensor cell pulses, neurone signal trains, plexus signal composition build the world IMAGE, in your brain.
Stereo is an aspect of (a perspective on) a holographic signal.
Stereophony, stereography, stereodactyli (touch) and stereo sense of smell.
More important than the signal, is the virtual space phase information encoded within it.