the first time i listened to music in a serious way - it was Casals playing a solo piece - i found myself totally concentrated on the music in such a way that the music was me and i was the music (a bit like what they say about some martial arts masters), and i could then listen not only to the melody and the notes being played, but also the birth, life, and the end (death) of every note. every note was different and had its own story, its own life.
it's as if Casals was directly connected to me, and sending me all he felt while playing the cello.

Total concentration...

i understand that this is quite common among musicians.