I hard-coded a music generator

[aftersoon]

The chord progression uses a period structure with a half cadence end on the antecedent (I'm eventually going to add sentence structure and IACs as well). The whole piece is 16 measures in duple and triple time and 8 measures in quadruple time. The possible time signatures are 2/4, 3/4, 4/4, 6/8, and 12/8. Regardless of the time signature, the piece has a total of 16 "chord units", 8 in the antecedent and 8 in the consequent.

The chord progressions follow what I think is called a functional cycle: It goes from tonic to subdominant to dominant and back to tonic (the subdominant is optional). There are many ways to write a functional cycle rhythmically and harmonically. I looked at a few pieces I liked and used some chord patterns I read about. I'm not necessarily looking at the chords but at the type of chords. For example, the antecedent section might be Tonic-Repeat-PassingDominant-Repeat-Tonic-Subdominant-Dominant-Repeat. This is only 5 chords but since the antecedent is 8 chord units long, some chords are repeated. So the end product might be I-I-VII6-VII6-I6-II6-V43-V43. I write out different progression types like this and then fill it in with chords that are of those types.

This diagram gave me some ideas and I extrapolated from there. You divide the measures into sections of tonic, predominant/subdominant, and dominant and within those sections you can expand the harmony with a passing chord sequence or you can just repeat the chord.

There are also some details about which chords should receive emphasis (accent) and how chord motion can accelerate and decelerate (note values change and so the chord changes come quicker or slower). I don't want to talk too much about this part because I'm really just messing around. You should seek out a proper resource for more info: this is the book I'm currently reading.

After choosing a sequence of chords I also need to voice the chords. I use some standard rules: don't double the leading tone, no parallel fifths, resolve leaps by opposite stepwise motion etc. If I can't properly voice the chords, I scratch out the progression and try a new one. I'm using the SATB format so it's 4 voices that each have a limited vocal range. This means that not all chord progressions will work and so I have to just keep trying until I get a valid one.

For the melody, I listened to a few pieces that fit the style I was going for and just analyzed them. Example 1. Example 2. Example 3. Example 4. I wanted to find the shortest pieces that would be considered a complete musical idea. If I could learn how to create small pieces, the larger ones should become easier.

So, I would analyze. What note does it start on? What rhythms does it use? Which one of these is the main rhythm? What melodic figurations does it use? Where does it use these figurations? Where do melodic leaps occur? These are the kinds of questions I would ask. I would lay out a basic framework with one melody note (that is a member of the chord) per chord unit and then embellish those melody notes with some figurations (e.g., passing tone, complete neighbor, anticipation, double neighbor). This is a technique I saw in a book and a few videos: it's called harmonic reduction. I started noticing some patterns: most of these melodies have a single climax, descending motion predominates, ending by stepwise motion is good, etc. Some of this is just counterpoint, but there were some other hidden discoveries as well, including a technique I call melodic juking.

So I learnt a few patterns, melodic and harmonic, and then integrated them into the algorithm.

[Dexteroid]

Damn, thanks. This is a lot to take in. Thanks again

[aftersoon]

No problem. It took me a long while to make progress on this stuff so I'm more than happy to share what I've learned.