The next part of our adventure into harmony deals with chord substitutions. We’re going to take the typical blues-oriented I7, IV7, V7 progression and do some substitutions for the IV chord.
The chords in this progression are (key of C) C7 (C, E, G, Bb), F7 (F, A, C, Eb) and G7 (G, B, D, F). If we build a four-note chord on the second degree of the C major scale (D), we get Dm7 (D, F, A, C). Notice how similar the Dm7 to the F7. F A C is common to both, giving us the basic tonality of an F major chord. The difference (other than the root note) is D instead of F. The D is actually the fourth above F, which will tend to give the chord a slightly less resolved sound in contrast to the FM7. Additionally, D is the next scalar step above C.
The first half is an example of the standard blues progression in C – C7, F7, and G7. The second half substitutes Dm7 in second measure for F7.The C#7 chromatically leads to the Dm7 in the second measure. In the sixth measure, the Dm7 substitutes for F7 again and the Dbm7 gives a chromatic movement downward to the C7. In the twelfth measure, the Dm7 – Em7 – Abm7 leads to the G9 at the end.
Watch the video and listen:
You can download a pdf of the sheet music here.
Work through these examples and get a feel for the substitutions. The next post will deal with further substitutions.