7-4 · Harmonic and Melodic Minor: One-Note Edits

In minor keys, the dominant seventh goes missing. In the key of A minor (same notes as C major), the diatonic seventh chord built on the fifth scale degree is Em7, so a diatonic five-to-one cadence is Em7 to Am. It's pleasant enough, but the Em7 doesn't really pull toward the Am. If we make it a dominant seventh instead (E7 to Am), it pulls much harder toward home. But E7 isn't in the key of A minor. So where does it come from? Answering that gives us the first genuinely new scale of the course, and the third operation on the map: edit.

Think about the major scale for a second. Its seventh note sits a half step below the root and leans into it like it can't wait to get there. That note is called the leading tone. Natural minor doesn't have one: its ♭7 sits a whole step below the root and doesn't pull nearly as hard. So the fix is small. Raise the seventh a half step — in A minor, G becomes G#.

Look what the first edit does to the chord built on the fifth degree: E–G–B–D becomes E–G#–B–D, which is E7. That chord now has the two most restless ingredients in music — a leading tone that wants to resolve to the root, and, between the G# and the D, the interval called the tritone, famous for demanding resolution. That's where the pull comes from, and it's where the name comes from too: the harmonic minor scale makes the minor harmony work better.

The edit has a side effect. Look at the space between the ♭6 and the natural 7: three frets, a minor third, called an augmented second in this context. No seven-note scale we've met has a gap that wide. You know this sound. It's the instantly recognizable, slightly exotic flavor of flamenco, surf, neoclassical metal, and film scores. That gap is the sound. It's also a fingering wrinkle: every seven-note scale until now moved in one- and two-fret steps, and this one has a three-fret jump.

For centuries, composers loved what the raised 7 did for the harmony but were less thrilled about melodies leaping across that gap. So they ran the edit again: raise the 6 as well, and the gap closes. Smoother melodies — so this one is called the melodic minor scale. (If you took classical lessons, you may have learned melodic minor with the raised notes ascending and natural minor descending, which is how classical composers used it. Modern players mostly treat it as the same scale in both directions, and that's what we'll do.)

The stretched rectangle and stack

Back in Module 3, we built new pentatonic scales by editing old ones. Here's a variant we could have built then, but didn't: take the minor pentatonic and raise the ♭7. There's no standard name for this scale — I call it the minor-major pentatonic, because it contains all the notes of a minor-major seventh chord (a minor chord with a major seventh on top): 1, ♭3, 5, and 7, plus the 4. The rectangle stretches, and the stack gets skinny in the middle. A little less tidy, but they're the same two building blocks, and they connect across the neck by the same rules.

Now the reframe pays off. To turn the minor pentatonic into Aeolian, we added the 2 and ♭6 in the staggered position. Do exactly the same thing inside these stretched shapes, and you get harmonic minor. To turn the minor pentatonic into Dorian, we added the 2 and natural 6 in the upper position — same move here, and we get melodic minor. Nothing about the added notes changed. We just stretched the frames.

Just like every scale in this course, this isn't a one-position trick. The rectangles and stacks connect vertically by the rules you already know, so you get five in-position forms, same as always, and the diagonal connections work the same way too. Here's Form 1 of each scale:

There's another way to arrange the stretched rectangle, with the natural 7 moved up a string instead. It's not really a rectangle anymore (it's more of a triangle), but you might find it easier on the fingers. The added notes stay in the same place relative to the root and the 5. Try both versions and stick with whichever works for your hands; these are the reference diagrams I promised in the video.

You might be wondering about 3NPS versions of these scales. They exist, but unless you're planning to shred neoclassical metal like Yngwie Malmsteen, I think you can skip them. These scales don't get used enough to justify memorizing more patterns — and if you ever do need them, they work exactly like the major-scale 3NPS patterns you know, just with more awkward fingerings.

When to reach for them

Harmonic minor is mostly a visitor: in a minor key, you use it while the five chord is sounding, often for just that one bar, and go back to natural minor everywhere else. The scale really exists to serve that cadence. Melodic minor, in this basic form, is even more of a specialist, mostly a jazz color. But it's the parent of two modes useful enough that we'll come back to them later in this module.

This is also why we're not going to harmonize these scales the way we harmonized the major scale. You could, since the skip operation works on any scale, but most of the chords that fall out barely get used. In practice, minor-key harmony is natural minor's chords plus that one borrowed dominant.

One more idea, because it sets up the rest of the module. Here's one octave of A natural minor; raise the 7, and it becomes harmonic minor:

Now remember the rotate move from Module 5: if you start a scale from a different note, you get a mode. Since harmonic and melodic minor each differ from a major-scale mode by one note, every one of their rotations also differs from a major-scale mode by one note — and as we'll see, they're often named in a way that tells you exactly what to change. So for most of these scales, you'll be able to use a familiar pattern and just change one note, and you can use the diagonal pathways from Module 5 to turn one octave into three whenever you need to. I'm not asking you to learn fourteen new modes. But hold onto the principle, because in the next lesson, one of those rotations turns out to be the most useful exotic sound in guitar.

Exercise 7-4: Put on an A minor drone. Play Form 1 of A harmonic minor slowly, and when you reach the G#, stop and let it ring against the drone. Feel how badly it wants to resolve — then resolve it. Do the same with melodic minor, and notice what changed when the 6 came up. The goal isn't speed or coverage; it's getting these two sounds into your ears.

Exercise 7-5: Practice the edit itself. Pick another key, find natural minor in any position, and raise the 7. Try starting from the Dorian mode and raise the 7 to get the melodic minor scale. If you can make the edit from memory, you know the scale.