I’d imagine that most readers of this site are familiar with the Circle of Fifths, but lesser-known amongst non-jazz musicians is saxophone giant John Coltrane’s variant on the tonal clock, the “Coltrane Circle.”
Coltrane was notoriously hush-hush about the theoretical aspects of his music, but a wonderful new article by Roel Hollander explores the possible meanings behind this clock. Though the reasons for why Coltrane drew it remain unknown, at the time, he was exploring a number of new influences – including Indian music and Einstein-inspired mathematical ideas.
On the left, Coltrane’s original hand – on the right, a rendering by Corey Mwamba.
The clock comprises two concentric rings, which form two whole tone scales in C and B. Trane drew rings between the overlapping leading and supertonic tones (the major 7th and minor 2nd), of these scales, which themselves also outline diminished 7th chords. Adding to the curiosity, if you “zig-zag” counter-clockwise between the harder-outlined rings, you get the Circle of Fifths.
The circled tones may also refer to a compound scale, formed by combining the natural minor and melodic major scales, characteristic of North Indian music at the time. But of particular interest for rock and metal musicians is that if you draw lines between the same tones in the Coltrane circle, you get a freaking pentagram. Trane himself didn’t add those lines (it’s unclear who did), but they are there nonetheless.