Last month, I introduced the 12-bar jazz-blues progression, which is a more musically sophisticated cousin of the simpler “one-four-five” blues chord changes that most people are familiar with...
Last month, I introduced the 12-bar jazz-blues progression, which is a more musically sophisticated cousin of the simpler “one-four-five” blues chord changes that most people are familiar with and serves as a more harmonically ambitious framework that jazz musicians almost universally prefer to solo over and use as a vehicle for improvising rich, colorful melodies that allude to interesting chord substitutions.
I’ll now continue where we left off and present a few commonly used variations on the jazz-blues progression that adventurous musicians will often interject.
FIGURE 1 is traditional “flat-four” comp (accompaniment) figure that’s a variation on FIGURE 2 from last month’s column and offers additional examples of chord substitutions that learned guitarists will add to a jazz-blues progression, with numerous subtle variations, in a two-guitar jam (no bassist or drummer).
Again, we’re using what arrangers call shell voicings, which include only a chord’s root, third and seventh (often voiced, low to high, root-seven-three) and what guitarists call “muted-string chords” because unused strings are muted with the fretting fingers, just like when you play a strummed octave.
Noteworthy chord substitutions used here include the following:
• A “two-five to the four chord” in bars 3 and 4, with Dm7 and G7 setting up the change to the four chord, C7, in a more harmonically active and interesting way than just preceding it with two bars of G7. A similar move occurs in bar 8, in this case with a “two-five to two.” Here, we approach the two chord, Am7, with Bm7 and E7.
• The “sharp-four diminished seven” chord in bar 6 (C#dim7), which is an outgrowth of the four chord (C7) that builds dramatic tension, which then resolves satisfyingly back to the one chord (G7) in bar 7.
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