Anyone here play the SNES version of SimCity? No, it didn't have procedural music, but it did have different music for each progressive city size, and they were essentially variations on a theme (it started out like a sleepy little tune, then started rocking out with orchestral hits when your city got real big). This made me think of that.
TIE Fighter had the benefit of an existing and very nice symphonic score from the movies. I think that before we do this, we need to have some more actual musical scores ourselves. Yes we have the vanilla DF music, but that's just one source to draw from. It says to me, "small fortress, mildly unhappy dwarves, the underground is cramped and kind of damp and it's none too pleasant outside". So...I guess, what variables do we want to control on, and how does it change the sound? Do we want it to all stay about the same in basic melody, or do we want multiple distinct melodies that blend into each other? Is it a good idea to have different music for good/evil terrain types--I'd figure no, because it means you will only ever be hearing one for an entire fort (unless you change it just scrolling around which I think would become very muddled).
I dunno...the thing is, for the most part, DF does not have big dramatic moments like TIE Fighter does. You get sieges how often? Dwarves die how often? (Yes I know they die all the time, but you know when it's coming most of the time, and it's not THAT that often, it's multiple minutes between them--or ten dwarves in the blink of an eye.) So, to me, it's just an ongoing theme, and here's the important parts:
- Fort size, so you get a progression as you play.
- Happiness.
- Let's combine those two: Happy dwarves alter the music one way, unhappy dwarves modify it in an orthogonal way. So if you have a lot of happy dwarves you have your basic music, but if a few become unhappy all of a sudden, it starts to add some darker jabs. These would make a good rhythm.
- Labor! If you've got a big mining project going on, it should sound like it. If you have a distinct farming season, that should be noticeable.
- Danger. Same thing as Labor really--add or modify the melody when there's fighting or dying.
- TIE Fighter style events with ~10-second musical scores when traders arrive on the map, become ready to trade, and during various siege events, including squads being routed. Nothing special for your own dwarves dying, unless it's a big squad or something. You can also go the L4D route and add ominous noises when ambushers start sneaking around--even before you see them. Also, cram something minor into the next melody bit whenever a moody dwarf stashes another item.
...I think I know what song I keep thinking of! "
Work Day" from Rise of the Triad. If there is a dwarfier song, I haven't heard it. I like this song for large (120ish?) forts. If's got a solid rhythm that you can screw with, and you can tweak the instruments of the melody for different labors.
.....and if you really wanted to be a dork, you could look at disney's Seven Dwarves and their "Hi Ho, Hi Ho!"ing for a super-happy tiny fort...