To wrap up April, Jazz Appreciation Month, I made a video using Music Compass to demonstrate a bass line walking up major tetrachords: Do-Re-Mi-Fa. The interval between Do and Fa is a perfect fourth — this is the “rising fourth”.
Harmonic motion over a rising fourth occurs twice in the ii – V7 – I chord progression so ubiquitous in jazz. A remarkable example of this ii – V7 – I progression is in the Ray Noble jazz standard Cherokee, in which the B section and reprise of the A section are a long chain of 12 ascending fourths!
In this demo video below, you’ll hear the bass line (played on cello!) walking up sequential major tetrachords.
The harmonic motion, indicated by the movement of the red tonic piece, is in rising fourths: starting at C and moving to F, a perfect fourth, and then from F to Bb, a second perfect fourth. You can follow the major tetrachord shape being rotated on the Music Compass. The pattern of rising fourths continues from Bb to Eb, Eb to Ab, Ab to Db, and so forth. The sequence of tonal centers is known as the Circle of Fourths, and it goes through all twelve major keys. It ends back where it began, on C.