Classical music is mostly boring to me. While I can appreciate the intricacies of the different threads running through the most complicated pieces, for the most part, the whole is uninteresting to me.
There are two exceptions to this.
The first is the when the music tells a story, an unintentionally vague description that doesn't really describe the exeception well. Certain pieces of music tell a story, a story that is often different for each person that heard it. In the music you can hear the struggle, you can hear the victory, the defeat, the success, the utter failure and the blinding glory.
Some music has it for only a moment, a small part where the heart catches the notes and recognizes that moment as its own. The strongest example I can give is the guitar solo that begins nominally at 6:19, but doesn't really start until 6:48, of November Rain, the original lyrics, from Use your Illusion 1 from Guns and Roses. At 7:08, it begins, and you can feel the struggle, that has a release at 7:36. That release, that moment, gives me the chills every time I hear it.
There are a couple others similar to that moment, but few with the effects that have lasted decades.
2:12 of Running from the Scene of the Crime from Manic Bloom has the struggle, the unrelenting build up that starts to release at 2:36. It isn't as dramatic as November Rain, but the bass and piano play that becomes prominent at 3:15 still sway the heart. I say that, but the most visual part I think is from 1:27 to 1:40. I always see Harry Dresden with his staff fending off the Red Court, usually with Ramirez close by (and if that made no sense to you, that's fine, go read the Harry Dresden series).
Along with the story-telling style of music, the other exception to the classical music dislike is the intertwining, overlapping duet melodies. Unfortunately, I don't know the term for it (but am hoping that Matthew Albert will help me out here), but can describe it at least.
The music has two people are singing (though it could be two instruments), different parts that interweave and overlap, each singing parts where words overlap sometimes.
The first is the scene from Les Misérables after Fantine dies, where Javier confronts Jean val Jean. The two actors sing different parts, with one singing loudly when his words are more important. Kris says the best choreography he saw of this was when the two characters circled each other around a table or bed, and the actor upstage facing the audience was singing more loudly, his words carrying to the audience.
A more modern version is My Eyes from Dr. Horrible's Sing-a-long Blog, where Dr. Horrible and Penny's words are completely overlapping in the third verse. You can concentrate on one melody, listen to it weave through the song, then relisten to the song and listen to the other melody, and the whole mood changes. The one is tortured with unrequited love, the other is joyous in its newfound love. The song is delightfully amazing in it's telling.
The best classical music is the one that combines both of these delicious quirks, though music isn't the only way the interweaving can happen. And the story-telling doesn't have to be the normal plot line of introduction, increasing tension, climax, and denouement. When they're circular in the rising and falling fashion, the story can be surprisingly entertaining. Mostly, when the starting and ending parts are the same, I am amused.
The Jabberwocky is an example of the start and the end being the same, which holds in the same vein:
’Twas brillig, and the slithy toves
Did gyre and gimble in the wabe;
All mimsy were the borogoves,
And the mome raths outgrabe.
The start of the poem, there's calm. You feel the slow meditative feel of the story begining and after the horrific, violent death and morbid celebration of said death, the world calms back down to the quiet, Bambi-esque, happy songs playing in the background after the tempest.
It's that moment after the crashing thunderstorms have run amok, when there's quiet and peace and certainty. It's the point in story in the classical music piece when the cacophany of the middle torture is over, and the slower calming part has arrived.
It's a good place, this place of peace.
It's been a long time coming, too.
It's nice to be here again.
Matthew comes through for me, as I knew he would:
Hey Kitt! What you're describing doesn't have a term specific to vocal writing, as far as I know. It's a duet, but the particular kind of interweaving is called counterpoint. If two musical lines are following the same rhythm but on different notes, they're in harmony with one another. It's when each line has more independence, sometimes going up when the other goes down, or holding a note when the other moves between notes, that you get counterpoint. There's also a term called invertible counterpoint, which is when the counterpoint works in such a way that either line could be transposed up to a higher or lower register and it would still work as counterpoint. Most counterpoint works this way. Classical composers like Bach were famous for this kind of writing, and this is something musicians study in theory in undergrad. So I'd describe these duets as vocal counterpoint.