Thank you for expanding on this for me. You bring up a lot of good points that I have struggled with as well.
All of these assumptions, unfortunately, break down very quickly
This was something that was at the heart of the issue as you brought up. I think for me, the path I was going to go down was to make simple tools that made these kinds of egregious assumptions and hold each tool in a rigid compositional box.
- A melody uses only one scale
- A melody uses only pitches contained in the scale
- Each pitch in a scale is an equally viable possibility
- A variation should maintain the same scale steps, in the same directions, as in the original
Make all of these assumptions explicit from the outset so that the user of the tool understands the limitations and scope of when this tool would be useful.
I have been thinking of these in terms of my own musical compositional understanding. For example,
when starting to write a composition, I follow these explicit rules.
- Create a harmonic progression
- Create a harmonious melody to the composition that follows the following rules
- Melody notes must harmonize with the accompanying chord
- A melody can use passing notes as non-chord tones
Then create a tool that follows these rules.
Then as my understanding grows, I would create a tool that would have less assumptions, and less rules. However, every tool by nature of automation is always working within a box of pre-defined assumptions.
This would allow me to ignore the problems of each assumption initially to create a framework that works well in some contexts. Also, making all of these assumptions bold and clear to the user so that they knew that they were being creatively limited in some context. As long as they are aware of the limitations, they then had the ability to choose a different tool, or use it as a framework to then manipulate and create their true work. This is where the true works are, when people work within a framework, but then know what assumptions they are working with so that they can then break those rules to accomplish their true goals.
I think by nature of music, no tool will cover all contexts, nor should they.
There is also one more big problem lurking in the background. I know you are focused on western music and notation which does help limit this problem a lot. However, different genres and cultures have different means of understanding harmony. It seems like your training is heavily into the jazz culture of harmonic ideas which then brings with it it’s own framework for understanding these relationships of diatonic and chromatic harmonies. I don’t think that there will ever be the one model to rule them all to model.
I do think you already have a strong understanding of what the limitations are for each are which gives a good basis for the context in which each tool is most applicable to the particular composer which is using it.
Every time you remove one of those assumptions, the model complexity explodes. This also breaks each large assumption into many smaller assumptions, each with their own baggage.
- This song only uses a single scale
- Modulations would then be mode shifts
- How do we consider stable and unstable melodic notes
- Which harmonic model are we using for accompaniment
- This song uses key changes
- When is a modulation a mode shift or a key change?
- Should this be modeled locally or globally?
- This song uses a chromatic melody
- Which model of adding chromatic notes are we using?
- What implication does this have on the relationship of the chromatic note in relation to the diatonic note?
- This also brings in assumptions that the chromatic notes must actually be related to diatonic notes
- This also assumes that we are using the diatonic major/minor scales as a musical foundation
- If we allow other scales other than diatonic modal keys, how do we then abstract this tool to account for all the scales and their accompanying chromatic counterparts
- Does this then devolve into a richer model of musical set theory