Music of the Ainur: Rap? Country? Opera?

[Arwen Imladris]

From Ainuluindale:

Then the voices of the Ainur, like unto harps and lutes, and pipes and trumpets, and viols and organs, and like unto countless choirs singing with words, began to fashion the theme of Iluvatar to a great music; and a sound arose of endless interchanging melodies woven in harmony that passed beyond hearing into the depthes and into the heights...

That is what the music of the Ainur sounded like.