For me, reading this chapter was really hard going !
I play an instrument myself, but am not familiar with all that analytical vocabulary.
Since the musical examples were also mostly unknown to me, I took the trouble of listening to them on Youtube. I dislike Wagner's music, and this prelude seems more an amorphous sound mass than a melody to me, but perhaps that is apt for representing the very beginning? And as for Schönberg:
!
This reminds me of an experience I had some time ago at a concert of a symphony by Shostakovitch (actually too modern for my taste) The beginning was quite harmonious, but then dissonances started and got ever worse and louder (representing oncoming war, as far as I recall) I remember that I was struck by the thought that this was how Melkor's interference could have sounded.