Calculating bars

For the piece to end up somewhere between six and seven minutes, each section should be around 30 seconds in length. Knowing now what the tempos will be, I can also determine how many measures I can fit into each segment.

With so many different tempos, it's likely that there will be a lot of irregular phrase lengths, which I like. The first A section will be 12 bars (the blues form once again, coincidentally!). B will be 7 bars the first time, then 14. C will be 27 bars, etc.

Later, when I start working with thematic material, it's possible that I might change these structures, perhaps add or subtract a bar here and there. That's OK, I don't mind doing that. But my initial goal will be to try to keep them intact, as much as possible.