Many blues songs are built around major-key chord progressions based on dominant seven chords. A dominant seven chord has a root note (1), a major third (3), a perfect fifth (5) and a minor, or “flatted” seventh (b7). For example, if the root note is E, the remaining chord tones would be G# (the 3), B (the 5) and D (the b7); when played together, these four notes sound an E7 chord. A great way to add dimension to a solo is to play a melodic line that outlines a series of dominant seven chords, wherein the melody, as the highest note, is harmonized by additional notes below it, derived from dominant seven chord shapes. This technique is well served by the use of chromatic movement between the dominant seven voicings, whereby they shift up or down in half steps, one fret at a time.
No let’s apply the concept to a musical idea. In FIGURE 2, an E7 chord shape is played on the top three strings in a fingerpicked, arpeggiated manner, with the addition of the open high E string. This shape then moves down chromatically to a first-position E major triad and a single-note phrase based on the E blues scale (E G A Bb B D).
We can voice this type of melodic/chordal idea higher on the fretboard by moving the shapes over to the D, G and B strings, as shown in FIGURE 3. The dominant-seven chord shapes descend chromatically in bar 1, and the phrase rounds out in bar 2 with another E blues-scale lick, played in this position.
In FIGURE 4, the concept is moved over to the A, D and G strings, wrapping up with bluesy single-notes licks played in ninth position. FIGURE 5 exploits the chromatic approach further. Beginning in 16th position, we steadily move down the neck chromatically across four bars, landing in first position and culminating with a flashy, pull-off/slide lick based on the E blues scale.
Try devising more ascending/descending chromatic phrases using these approaches.
