News for hackers. Stuff that matters.
Re:John Coltrane Draws a Picture Illustrating the Mathematic... by zengid on Friday April 14, 2017 @09:47AM (#14114393)
I'm trying to parse out the logic, but it looks like the outer ring and inner rings are moving clockwise in whole steps, with the outer ring starting on C and the inner starting on C#. If we took the rings and straightened them out we'd have (its hard to tell some of the notes so correct me if I'm wrong):

  [1]                     [2]                     [3]                     [4]                     [5]                     [1]
   C   D   E   F#  Ab  Bn? C   D   E   F#  An? Bb  C   D   E   Gb  Ab  Bb  C   D   E   F#  G#  Bb  C   D   E   F#  Ab  Bb  C
     C#  Eb  F   G   A   B   C#  Eb  F   G   A   B   Dn  Eb  F   G   A   B   C#  Dn  F   G   A   B   C#  En? F   G   A   B  
Note:

  n = (natural sign)
  ? = its hard to read the scribbles.
It looks like he augments some of the intervals in the middle of the scale and diagramming how to elide from one to the other. Note that Bn could be considered distinct from B. Coltrane was familiar with the overtone series that generate what are called harmonics. Harmonics could be thought of as the sine waves that sum together to create the timbre of a pitch. If you've played guitar and you pluck the string while gently pressing the string down at the 1/2, 1/3, 1/4, 1/5 (etc) division, you'll force the string to vibrate only at the frequency that corresponds to that harmonic (ie 1/2 would force it to vibrate only at 2f where f = the lowest vibration mode of the string, sorry If I'm not conveying the physics perfectly). Anyway, the overtone-series closely approximates a major scale, but it gets tricky when you want to shift from one series to the next because the series is generated from integer ratios, and prime numbers generate similar but distinct pitches. Long story short, you can have several genus of the same note that are all mathematically distinct.

..I've got a better description here https://music.stackexchange.com/a/33787

Re:John Coltrane Draws a Picture Illustrating the Mathematic... by fixed_carbon on Friday April 14, 2017 @12:35PM (#14115420)
I'm pretty sure both rings are normal whole-tone scales and all the places you have marked as Xn are simply Xb.

Curious though if you have a take on the boxed numbers over the C's. Perhaps calling out how the original tonic position changes in relation to everything else as you move around the circle?

Re:John Coltrane Draws a Picture Illustrating the Mathematic... by lucasgonze on Friday April 14, 2017 @01:05PM (#14115597)
The boxed numbers are octaves. This graph stretches the 12 semitone octave-image that we're used to seeing out to 60 semitones.
Re:John Coltrane Draws a Picture Illustrating the Mathematic... by fixed_carbon on Friday April 14, 2017 @03:05PM (#14116412)
"out to 60 semitones" -- does this mean you're interpreting the diagram as a pitch-map covering five octaves? I was interpreting it as a tone-map comprising 12 semitones grouped into five distinct tonal regions with the center web indicating specific movements from one tonal region to another.

EDIT: Just saw your other comment interpreting it as a spiral, which effectively answers my question.

Re:John Coltrane Draws a Picture Illustrating the Mathematic... by lucasgonze on Friday April 14, 2017 @03:51PM (#14116750)
Yes, that's the way I interpret the diagram.

I think the importance of there being five tonal regions is that this enables the multiples of 12 to line up at 60. These numbers are significant because they connect back to the Babylonian sexagesimal ("base 60") system used in both music theory and trigonometry.

https://en.wikipedia.org/wiki/Babylonian_numerals