Note: this post was originally published on Gig-Ready Jazz Bassist.
I’m starting a series on “theory bass-ics” – the rudiments of music theory that are especially applicable to jazz bassists. In this edition, I was to briefly explore the circle of fourths. The reason we use this system in jazz (and not circle of fifths (moving counterclockwise in the circle), as in classical) is because many jazz chord progressions are built on movements up fourths. The ubiquitous iii-VI-ii-V-I progression (demonstrated in ‘C’ in “St. Thomas” on the left side of the graphic) corresponds to the upper, left-hand quadrant of the circle of fourths.
As bassists, we have to walk many basslines over these types of progression. There are three common ways to get from ‘1’ to ‘4’ (I-IV):
- Up the scale: 1-2-b3-3-4 (for C-F, it would be C-D-Eb-E-F) [note that using minor and major third with work for major, dominant seventh, or minor chords]
- Up the arpeggio: 1-*3-5-b5-4 (for C-F, it would be C-E-G-Gb-F) [note that *3 means the third will vary according to the chord]
- Down the scale: 1-*7-*6-5-4 (for C-F, it would be C-B-A-G-F) [note that *6 and *7 means the sixth and seventh will vary according to the chord]
In addition to bassline construction, the circle of fourths is an effective way to practice material in all twelve keys (start with C, then F, etc.)
Can you think of ways to incorporate the circle of fourths into your practice?