I find music theory fascinating from a philosophical perspective because:
Anyway. And it’s all based on this odd coincidence that (3/2)^12 is almost equal to 2^7. If that weren’t the case, music would be indescribably different.
Jacob Collier does a great quick demo of how different the integer-ratio vs 12th-root-2 notes can sound: https://www.youtube.com/watch?v=XwRSS7jeo5s
Rhythm is also fascinating! It is so syntactical
I don’t think the circle of fifths is used outside western music. Can you explain why you say “nearly every human culture”?
12 tone equal temperament (which the circle of fifths arises from) has been around for a couple thousand years and has influenced a plurality of non-westerners. Especially after the internet, our music tastes have started to converge across the world. There are of course non-western cultures that don’t use 12 tones and thus don’t have the same circle of fifths, but if you listen to the radio in Eastern Europe, South America, East Asia, etc (big first-world cultural hubs), you’ll find plenty of pop songs structured very similarly to American pop songs. Bad Bunny and Higher Brothers are some examples of converging music tastes imo.
Sorry, I was being a bit lazy there. What’s universal is the use of simple pitch ratios as musical intervals. Every culture that has any sort of music has discovered & used pentatonic scales (or so I’ve read.)
There are interesting bigger circles of fifths with e.g. 19 notes and 31 notes in which C# != Db (and actually C# is lower than Db). Wikipedia equal temperament page has more info.
Also there’s some great music using various other equal divisions of the octave (EDO), some cool examples being Sevish’s Gleam in 22EDO and Brendan Byrnes’ Sunspots in 27EDO (lots of frets on that guitar!).
I find microtonality intellectually interesting, but I haven’t been able to adapt my ears to the point where it sounds good. The pieces I’ve listened to all seem kind of unpleasantly out-of-tune. Which I know is just because it’s unfamiliar, but it hasn’t incentivized me to listen further.
Indeed some microtonal stuff can sound pretty crunchy :p
One microtonal thing that immediately sounded lovely to me is Ben Johnston’s version of Amazing Grace (uses just intonation).