I’m sure you already know everything about how to harmonize the scale with triads (if, on the other hand, you have no idea what I’m talking about you can first take a look here), but have you ever tried using fourth chords instead?
I’ve already talked about quartal harmony, and now I want to put it in practice by harmonizing a scale using chords built by fourth intervals.
The use of these chords instead of the usual triads gives a different sound to the scale and is perfectly suited for modal situations.
The following examples are in the key of E eolian and use the chord shapes already covered here.
The “basic” chord structure (starting from the fundamental) is: R – 4th – 7th – 3rd.
Here you see the seven chords of the harmonized E aeolian scale going up the neck using adjacent strings.
If you play the chords with the 3rd on bass, you’ll have: 3rd – 7th – R – 4th.
The following example starts once again from the pitch E, but this time it is the 3rd of a C7(#11) chord.
I somehow use the term “second inversion” in an improper way, because here the chord does not start from the 5th but from its 4th and looks like this: 4th – R – 3rd – 7th.
Starting from E, the first chord is Bm7(11)/E. It is interesting to notice that the notes E-A-B-D can also be seen as E7sus.
Finally, the fourth chords with the 7th on bass have the following structure: 7th – 3rd – 4th – R.
The first chord in this example is F#m7(11).
After you get the basic idea and have memorized the shapes on the guitar, you can start experimenting with them and getting acquainted with the sound of these chords.
The first idea is to move around all the chords over an E pedal.
Then you can connect all the inversion of the same chord.
Or you can connect all the chords in the scale that share a common note; for example: take the bass note E and play Em7(11), then Cmaj7(#11)/E, Bm7/E and F#m7(11)/E. Then do the same with a fixed note on top.