Call me Ibrin or Ibri, it's a lot easier.
I think I'm going to have to do a bit of research on the historic origins of the organ. It may help shed a bit of light on the reference. My feel about the writing style of the Ainulindale has always been that it was intentionally Biblical in nature. An Elf, having been told or even given a vision of the Great Music, would no doubt have been rather overwhelmed and befuddled -- in existence without Time or physicality, how does one sing? -- and would not have had the proper frame of reference to really comprehend it, so he would have retold the tale using concepts he and others would understand, I think. From what I do recall about the earliest organs, they were little more than reeds sounded by a bellows, and we do know that reed instruments exist in Middle-earth, since two of the thirteen Dwarves played a clarinet. In fact, in that mention alone, we have two different kinds of bowed strings (fiddles and viols, the latter being described as the size of modern cellos), woodwinds (flutes), single reeds (clarinets) and plucked strings (harp). We also know that percussion and brass are attested to elsewhere, though I have to wonder if all the brass is in the simpler, non-valved form (Feanor was a clever fellow, but would he have bothered himself with the invention of valved brass instruments?)
