So, say there's a musical piece that has the following structure:
[A.1] [A.2] [A.3] [A]
Where A is a "harmonic theme", in the sense that it's treated as a theme, but its melodic content is contained in the chords' voices instead of being played by a solo instrument.
A.1-3 Are all intended as "movements", each of them being a variation of (or, inheriting from) A.
Note: I call "alien" whatever musical content wasn't directly derived from the mother A
Instrumentation
Note: Sorry for my lack of terminology.
It's basically an orchestra composed primarily of:
- Strings section
- 2 pianos (1 of which is "prepared", as in John Cage)
- Couple of cymbals
- There are also sound effects and other nontraditional or "modern" instruments (in the context of an orchestra).
The structure
This is the big picture structure of the piece:
A.1
- It's about 3:30 minutes in length
- Inherits from A
- There is a solo instrument playing a melody clearly standing out from the rest of the orchestra.
- It introduces an alien progression (compatible tonality-wise) before giving way to A.2
A.2
- It's about 5:00 minutes in length
- Inherits from A
- It simply presents its two variations of the main theme.
- The same solo instrument appears briefly.
A.3
- It's about 6:00 minutes in length
- Inherits from A
- It plays its variation twice, first as a pizzicato strings + piano, then as staccato strings + piano
- It introduces an alien progression (incompatible tonally) which has one string group playing staccatto and another playing pizzicato, and there are tritones here and there, with an almost bartokian (ha, I wish!) feeling to it, which ends in a single note which happends to be the minor 7th of the main theme's root.
A
- It's about 2:00 minutes long
- It starts with an instrumental/sonic (there are sound effects in this piece) explosion which is also the first chord of the main theme
It's important to note that the "climax" (last part where the "mother" theme is presented) ends up sounding really primitive/simple, I suppose as a result of having spent lots more brain energy when working on its children.
So, my question would be:
What is the formal term (I've been told it could be called a Fugue) that would most accurately describe this structure?
Or, a more general (and useful) way to ask the question would be: What do you call a structure that presents a main subject at the tail of a piece, after several variations of it have occurred?