I'd say the elves and the West do present themselves as the "other reality" in contrast to humans of the ME and thus I'd say they are more of the first definition. But I'm not sure if the word "unworldly" can be used in relation to them. The West is an odd mid-stop between "the world of men" and "the world beyond"...
Let me offer another possible POV for organising one's thoughts about the elven music.
In the Pythagorean / Boëthian tradition from Antiquity we have three different kinds of "music" (spheres of it, notions of it, mode of being of it) which I'd guess the prof. was aware of with his classical education.
The pure music was the "music of the spheres", the non-audible cosmic music of the reality itself (
musica mundana by Boëthius).
Then there was the music of a living being (well a "learned human" in this real world of ours) in structural harmony with the universe and its principles (
musica humana for Boëthius).
The third one is the music we can hear as the music we normally think of as music; sounds and rhythms to be perceived, and to be played with instruments/human voice (
musica instrumentalis for B).
The first one is quite easy to identify with the music of the Ainur and the third with the music we people make (or any other ME creatures?). But the question becomes, is there the middle one? Is it the music of the Valar and Maiar (and elves?) in the West; eg. not the primordial music of the universe only Eru could organise (even if it included the Valar) but the music the purer forms of existence could have produced in the World and to teach to the elves there in the West? And thus the elven music in the ME would resound something of that purer form of music being at the same time in a way compromised by getting thus far away from the original (both being further developed by "mere elves" and being farther away from the source)?
Needs to think. The thought came faster than I could think it through...
