Musical instruments in Middle-earth

[Legate of Amon Lanc]

Interesting thread! I have maybe one or two more tokens to show.

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 Ilúvatar to a great music;

In other words: How could you forget that? Note the organs, mainly. Not that it proves that organs actually existed in Middle-Earth, but on the other hand... what would then be written in the original of Ainulindalë?
Just to make it complete, it was already spoken about trumpets; but to remind us, the trumpets are mentioned at the same place also in negative context:

The other had now achieved a unity of its own; but it was loud, and vain, and endlessly repeated; and it had little harmony, but rather a clamorous unison as of many trumpets braying upon a few notes.

And now for a change, from the goblin song in the Hobbit:

Hammer and tongs! Knocker and gongs!

I'm not sure if we can take "gongs" as given, but if not here, then surely at the very end of the Two Towers:

Sam heard a burst of hoarse singing, blaring of horns and banging of gongs, a hideous clamour.

From both of these, it seems like gong is an Orc-instrument. Orcs are generally shown as liking percussions. And that's of course not speaking of the famous "drums in the deep".