December 19th, 2024

Music and Geometry: Intervals and Scales

The blog post examines the link between music theory and geometry, detailing 13 musical intervals, their geometric representations, and the relationship between equal temperament and perfect geometric shapes.

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Music and Geometry: Intervals and Scales

The blog post "Music & Geometry - Intervals & Scales" by Roel Hollander explores the relationship between music theory and geometry, particularly focusing on musical intervals and scales. It identifies 13 intervals in Western music, ranging from unison to octave, and discusses their geometric representations through tone circles, specifically the Chromatic Circle and the Circle of Fifths. The Chromatic Circle visualizes the 12-tone equal temperament, while the Circle of Fifths illustrates the stacking of perfect fifths. The article emphasizes that perfect geometric shapes can only be achieved using equal temperament, as just intonated intervals lead to imperfect shapes. Various geometric shapes, such as lines, triangles, squares, hexagons, and dodecagons, are used to visualize the connections between tones. The Tetractys, a significant Pythagorean symbol, is also mentioned as a geometric representation of musical interval ratios. The post concludes that while just intonated intervals may sound more consonant, they do not yield perfect geometric shapes, suggesting a complex relationship between music, mathematics, and geometry.

- The blog discusses 13 musical intervals in Western music theory.

- It highlights the geometric representations of these intervals using tone circles.

- Perfect geometric shapes are only achievable with equal temperament tuning.

- Various geometric shapes illustrate the connections between musical tones.

- The Tetractys is presented as a significant geometric representation of musical ratios.

Link Icon 16 comments
By @Duanemclemore - 2 months
Amazing. A deeper dive of the methods John Coltrane used.

https://www.openculture.com/2024/12/john-coltrane-draws-a-pi...

And

https://www.openculture.com/2017/10/john-coltrane-draws-a-my...

With plenty of great links to dive deeper in both!

By @rekado - 2 months
If you like this you may also be interested in Emmett Chapman's Offset Modal System:

https://www.stick.com/method/articles/offsetmodal/ https://www.stick.com/method/articles/parallel/

By @niobe - 2 months
I am a technical musician for 40 years and I couldn't understand the points he was trying to make... poorly explained
By @jrdres - 2 months
I don't know enough music to tell if this is insightful, or just neat pattern-matching.

A few months ago, mathematician John Baez had a series on the mathematics of various temperament and keys. Of course he knows his math, but also music thanks to being a member of rather famous musical family. (More math in the second link.)

https://johncarlosbaez.wordpress.com/2024/01/11/well-tempera...

https://johncarlosbaez.wordpress.com/2023/10/07/pythagorean-...

By @pohl - 2 months
I love this. Here's another interesting thing I encountered. It's a way of organizing chromatic subsets by brightness

https://www.reddit.com/r/musictheory/comments/1etydas/i_made...

By @tugu77 - 2 months
The diagrams look nice, but in the end of the day, they are merely nice visualizations of what's fundamentally algebra. There is not much geometry going on besides a quite simple group structure of order 12.
By @tambarskjelve - 2 months
I understand music and mathematics were much more closely related historically, to some extent practically regarded as the same subject, but new discoveries about this relationship are still happening in our time. One interesting finding is that the the Pythagoeran comma, i.e. tiny interval between to enharmonically equivalent notes can be constructed geometrically: https://link.springer.com/article/10.1007/s00283-022-10260-4
By @giancaIta - 2 months
Oh that's my cup of tea, love this stuff!

I've created a 3d guitar fretboard here, where the height of the blocks corresponds to the height of the pitches: https://www.fachords.com/guitar-fretboard-3d/

And here are the shapes of the different chord qualities in the Circle Of Fifths: https://www.fachords.com/circle-of-fifths-chord-shape/

By @aanet - 2 months
Fantastic resource! Thanks for sharing this. I love both the math, the music, and math&music combo. Tickles my inner geek. <3

I'd love to see if anyone has done this geometric / visualization for Indian classical (specifically, Hindustani) music??

Perhaps there's specific shapes / visualizations in certain Ragas that naturally emanate?

Note that in the Indian classical (Hindustani) music system, the Ragas are a "framework" for melody, not really a mode (as in Western music theory).

By @ChocMontePy - 2 months
I never realized until now that in the the two different circles pictured (the Chromatic Circle and the Circle of Fifths) the pairs of notes opposite each other are the same in each circle. For example in both circles B is opposite from F.

And if you move around the Chromatic Circle, swapping every second pair of notes with its opposite on the other side of the circle, you have the Circle of Fifths.

By @hilbert42 - 2 months
"Pythagorean Temperament"

'Pythagorean Temperament' involves the Pythagorean Comma (aka Comma of Pythagoras). Whilst mentioned, it's not spelled out as such here: https://en.m.wikipedia.org/wiki/Pythagorean_comma

By @BaculumMeumEst - 2 months
Somewhat unrelated: I’m looking for a comprehensive overview of why the CAGED system works on guitar. I see lots of mechanical explanations of how to use it to play various chords down the neck, but nothing explaining the theory behind it.
By @shermantanktop - 2 months
As a longtime guitarist, this is exactly the type of visual pattern crutch that the fretboard encourages and which is (for me) both a crutch and a trap. Geometry can help explain music but if it takes the lead, that’s the definition of formulaic.
By @f1shy - 2 months
There is a classical book by about the topic https://link.springer.com/book/10.1007/978-3-319-64364-9
By @ziofill - 2 months
I've been playing piano for 30+ years, and I only learned to use the circle of fifths this year. It's been short of a revelation and I can't recommend enough to practice scales and drills based on it.
By @brcmthrowaway - 2 months
How can I make music without knowing an instrument?