Neil's idea for a tune generator

[weiweichen]

Neil:

But even without resorting to ML, here are some patterns you might be able to exploit in a more logical tune generator:

Some notes appear more than others; in (very) rough order of precedence: root, octave, fifth, fourth, second, seventh, third, sixth. The cool thing is that there are actually many root notes working in a tune at the same time - the root of the key, the root of the phrase (usually the root of the chord that goes with the phrase, and there could be many but the most basic one is usually also related to the key), the previous note... I think you could create some measure of how much a note 'fits' harmonically into the tune based on that and skew your algorithm towards notes that fit. But don't totally exclude the weirder notes; they make it interesting and can twist a phrase into having a different root. The position of the note in the tune also affects how much it needs to fit. The last note of the part is heavily skewed towards either being the root of the key or, occasionally, the fifth (you know those tunes that just never want to stop repeating - they usually end on an unresolved fifth). The end of a four-bar phrase usually also skews more towards a root, octave, fifth or fourth.

The reason behind that is super-interesting, but I can't find any good short explanations (here's a longer but very interesting read: https://arxiv.org/html/1202.4212), You can derive it from the fact that we like frequency multiples of the root note and that our brains are bad at distinguishing octaves (which are ratios of 2:1).