When I first encountered melodic minor colors, I found myself wanting to access them all over the fretboard—but I didn’t want to be locked into always starting a scale pattern from the root. The way to do this, I discovered, was to harmonize the melodic minor scale and work from three- and four-note voicings built from the scale tones. Once I could visualize these small packages, I could tie them together and solo in different positions without relying on scale patterns. This chordal approach gave me a non-linear way to weave melodic minor sounds into a blues.
For example, let’s say we’re in the key of A, using a Bb melodic minor scale [Bb, C, Db, Eb, F, G, A] to carry us from an altered A7 to D9. Ex. 1 shows a Bb melodic minor scale, harmonized with three-note voicings on the fourth, third, and second strings. As you move through these chords, notice how every tone comes from Bb melodic minor. You’re actually playing three Bb melodic minor scales in parallel. Initially, some of the voicings—such as the first one, a rootless Bbm/maj7—may sound unusual, while others, like the Eb and F triads, will sound very familiar. But in the context of an A blues, even simple Eb and F triads generate altered tones.
Check it out: A bluesy I-IV line, Ex. 2 offers two altered tones, a #9 (C) and b9 (Bb). These occur in the last two beats of bar 1. Notice how the arpeggio on strings two, three, and four is actually the fourth voicing (technically, a rootless Eb7) in Ex. 1. The altered colors in Ex. 3—bar 1, beats three and four—revolve around the first two voicings in Ex. 1. In this instance, the altered tones are #5 (F) and b5 (Eb).
To get a firm grip on this chordal technique, harmonize the Bb melodic minor scale as we did in Ex. 1, but this time on strings three, two, and one. Once you’re familiar with the three-note voicings on both string sets, use them as a source for lines in the altered A7-D9, I-IV transition. Doing this homework takes time, but you’ll be rewarded with altered phrases that have little to do with running scale patterns.