Melodic Minor Quartal Boxes

A while ago I posted some general information about harmonizing chords in fourths. In this post I want to follow up on that, focusing on melodic minor modes in fourths as a way to create surprising voicings and give your chords some harmonic motion.

The idea here is to associate a particular melodic minor mode to each common chord type: major dominant, minor and m7b5. This will give us vocabulary for every chord type, meaning we can play through any standard tune using nothing but melodic minor quartal stacks if we want to, and that's a great way to get fluent with these.

In fact if we consider two different versions of dominant chords -- functioning and non-functioning -- and two minor chords -- depending on whether we hear it as the tonic or the ii -- then we have six chord qualities to consider. There are only seven modes of Melodic Minor; the "other" one is Mixolydian b6, so I thought I may as well include that one too.

In each case I look at three positions corresponding to C, E and A in the CAGED system, and for each position I give three quartal voicings on the top strings. Together these voicings cover almost the whole fretboard, so we don't really need to bother about the other two CAGED positions.

The colours aren't especially significant except that all the notes of the same colour in a particular box give one quartal chord, and I've used matching colours at the tops and bottoms of boxes to indicate overlaps.

Before learning these applications you should know the Melodic Minor scale, at least in the five CAGED positions, and be able to play the quartal voicings up the neck in any key. Of course, you should also be familiar with some more ordinary ways to play chords on jazz tunes; these are advanced sounds.

I recommend picking one application (i.e. one subheading below) and learning just the green form as a substitute; once this is internalized, add the forms above and below it to start joining the shapes together.

Major 7

There's no straightforward major 7 sound in the melodic minor scale; the closest is Lydian Augmented. The resulting chord -- 1 3 #5 7 -- can work as a sub for Maj7#11 or for a tonic major with a b13 on top, which is a very hip Harmonic Major kind of sound.

Dominant 7 (Altered Option)

Typically, when a dominant chord is functioning as the V -- whether it actually resolves or not -- it can take the altered scale (a.k.a. Super Locrian). These chords express the altered scale directly:

Dominant 7 (Lydian Option)

When a dominant chord is not functioning as a V, we usually think of it as a 7#11 or "Lydian Dominant" chord. Here we express this with the quartal voicings from the Lydian Dominant scale:

Dominant 7 (Mixolydian Option)

This is the third option Melodic Minor gives us on a dominant chord: Mixolydian b6. I like it as an alternative to the Lydian Dominant idea; essentially we're just using a b13 instead of a #11 while the 5 and 9 stay unaltered as usual. Be warned, this will cause consternation if you just throw it in unannounced when comping for another soloist:

Minor 7 (Tonic Option)

Here's Melodic Minor itself; these are beautiful chords to resolve to in bluesy minor-key tunes such as the A section of "Body and Soul":

Minor 7 (Dorian Option)

If you try the previous voicings on m7 chords that are functioning as the ii in a ii-V motion, you'll probably find they don't sound quite right. This is the sound I prefer on the ii. The b9 is a little hard on the ear at first but it's quite a cool sound -- it's the same pitch as the #5 of the V7 chord, which is a nice way to pivot into that.

Minor 7b5

Finally, here's the quartal version of Locrian Natural 6, a popular modern scale choice on m7b5 chords: