In any city, in any country, go to any concert or music hall you can get into. Once inside, find the head custodian and ask to see "The Holder of the Ethereal." He'll blink a few times, as if unsure if what you asked was real. Ask him again so it sinks in. Should he continue to stare and blink, you may wish to close your eyes and hold your ears shut before witnessing your innards being chewed apart by Hell's starving demons. However, if he should shake his head and turn to leave, go ahead and let him walk off, as it means your request was granted.
At this point, all you can do is wait. You'll notice the room getting darker and darker very, very slowly, but you can't be sure until some time has passed. As this is happening, the faint, nearly inaudible sounds of a tune will begin to play. This sound will grow louder and louder very, very slowly. Do not, however, strain to listen, for this will cause it to vanish and your ears to be ripped from your head. You must treat it as a background noise and nothing more, even though it will be the most beautiful song you've ever heard.
Soon, a low chorus of singing will rise to join in with the song. The lyrics these voices sing are the most foul of any you will ever encounter in your life, but just like the song, you must not focus on them. In heart-breaking and beautiful melodies, they will sing about every murder, every rape, every tale of false and broken love the world has ever known. Should you focus for even a second on any of the lyrics being sung, you will encounter the misery in that lyric a hundred fold until the day you die or go mad.
After what feels like a very long time, the song will slowly fade, but the lights will continue to lower until all is pitch black with the exception of a spot a few feet ahead, inhabited by dimly-lit shadows. Don't look too closely into it, for you may well go mad from the sight of the creatures lurking therein. A few moments will pass, and soon an eyeless figure dressed in formal attire will appear standing within this spot, holding at his side an old, rotting cello as tall as he. He will sit in a rusty chair that gradually takes form within the shadows as well. He will sit ready to play, but will not until you ask him one question: "Why do they sing?" He will smile a sad smile and instead ask you, "What did you think of my song?"
When he asks you this, you must respond with, "I didn't come just to hear old beauties." He will sigh and begin to play another tune, this one at once lighthearted and heavy, whimsical and heartbreaking. Whatever you do, you cannot listen to the tune he's playing at all, for everything will vanish in a flash and you'll find yourself standing in front of Satan himself, listening to his ear-shattering wails for eternity. He will speak slowly, but at length, about why they sing, about their attempts to drown out their sorrows and mourning with music. He will tell you how music is the one thing able to calm their blood-lust and their rage, even though they are doomed to sing the most horrible things imaginable.
Once he finishes talking, his tune should stop as well. If it doesn't, your death will be quick and painless by his hands and you'll join in with his chorus forever. If it does stop, he will rise and pack away the cello, then turn to you and take a bow. He will then slowly fade away into nothingness, as if never really there to begin with. The cello he left behind is yours to keep.
That cello is Object 166 of 538. Playing it will calm the very depths of your soul, but each time you play will cause the chorus from before to rise up in volume once again. And so, you should be careful--not only will they grow louder and more numerous as time passes, but the more you play, the closer you come to joining them...