If you look at the overtone series, specifically from the 8th to the 16th, you’lll notice that they fit into an octave and almost, but not quite, make up a major scale.. I’d like to look a little closer at that difference.

If we start on a C, the notes of the series are (almost)

C D E F# G Ab Bb B C

I say almost because they are not actually these notes…these are merely the closest approximations to the notes if you are playing a well-tempered clavier or its descendants. If you are playing something a little more flexible, such as a fretless string instrument like the violin, you can adjust your playing and play exactly these pitches.

The first thing that catches my eye in that series is that the fourth (F) is absent, and is replaced by the tritone (F#). This change alone would convert the scale from a Major to the Lydian Mode. This actually kind of explains how the Lydian mode is so bright: it is a half step closer to the harmonic series.

The other thing that I notice is that it has both the dominant and the major 7th. This change alone would convert the scale from a Major or Mixolydian mode to the Bebop Mixolydian.

If we use all eight notes and split them up into two alternating groups of four we get

C E G Bb and D F# Ab B

The first is the Dominant Seventh chord.

The second is could be written as Dmajor b5 13 but that really is a stretch. Maybe Bmin#13 is closer. Either way, it is a lot of tension.

These would be an interesting choice of chords to use for a four way close voice leading, alternating between them for runs up and down the scale. Or even just as a Lydian bebop scale. It does kind of explain why you can get away with a lot of leeway on a Dom7 chord…most of the intermediate notes are pretty closely relate overtone with to the primary chord tones.

I’m going to play around with it and see what I can do. I am not quite sure how to accompany, as there are several notes that need to be severely detuned to work right; the 11th, 13th, and 14 overtones are all >40 cents from the tempered tuning. We’ll want really flat tritones and the bebop note. We can also go with flat dominant sevenths or even harmonic sevenths. Although that really challenges the rules.

So, if we play on top of a C7 chord, the other overtone notes are the 9th, the Tritone, The #5 and the Major seventh. Not really “out there” from a jazz perspective, but maybe something to be aware of when selecting notes.

Playing it on piano is underwhelming, I suspect due to the perfect temperment. I need to try this with just an upright bass and Sax…