Oh wow, that was a bold choice for a season finale - just a sixty minute* shot of Celebrimbor looking at a chunk of ore that may or may not have been mithril** - though I offer my interpretations of the audio as follows:
The screaming - Galadriel stubbed her toe. Easily confirmed by the "Previously on..." segment showing Galadriel stubbing her toe mid-interrogation of Adar in the previous episode.
The banjo*** - Clearly the fourth theme of Iluvatar heralding the coming of the Illusalquë - the mountain-folk.
The chanting - That was just weird.
The buzzing/sparks - Celebrimbor needed a source of power great enough to power the tanning beds and it was only natural that he heed the Elven myth of the warrior vs the balrog and try to harness the lightning itself.
The silence - There was precisely twenty minutes of utter silence, this is for all the Rings of Power - 3 + 7 + 9 + 1 = 20
The clicks - Possibly Morse code for Finrod & Sauron's rap duel, though due to the well documented errors it could be attributed to audio of someone eating something.
Led Zeppelin's "Ramble On"**** - a little on the nose but appreciated.
The screaming again - Galadriel is really really clumsy for an elf. I suppose the writers think this "humanizes" her but it's just too silly to be taken seriously.
The rustling - The wind blowing majestically through the majestic Helmendil.
The Horn - It's the Horn of Gondor. What else could it be? *****
The voice saying "No Man Am I" - Yeah I have no idea. Anyone else?
Howard Shore's complete score of The Lord of the Rings movies - I found it amusing that this was compressed into nine and a half minutes but others may not find it so. These others are wrong.
Led Zeppelin's "Battle of Evermore" (see ****) - It appears that this cover was performed entirely on wet percussion instruments, which is an......interesting stylistic choice.
The other silence: Clearly someone forgot to push a button. Typical.
* for-longs in European time.
** Celeborn revealing himself to be Eol reborn means that galvorn is
not off the table, despite Gil-Galad's insistence of its extinction three episodes ago.
*** Maybe a Urukulele? Further research is needed.
**** If you listen very hard, the
tune will come to you at last.
***** If you bring up the horn of Helm Hammerhand
one more time I swear to all that's holy I will
end you.