This lesson is an introduction to chords built by stacking the interval of a fourth and the voicings that one can find by inverting them. While they can be used in other contexts, for the sake of simplicity we will be building them from modes and concentrating on what they are like when put on top of a static, droning root note. Furthermore, since it would be absurdly exhaustive to give examples from every single mode, we'll just be using E dorian.
So, the notes of the E dorian mode are E, F#, G, A, B, C#, and D. Instead of building chords from this by stacking 3rds, let's see what we get when we stack three consecutive 4ths using the notes of the mode. The notes that we end up with (in order) are E, A, D, and G. Using the highest four strings on the guitar, the following voicing is produced: xx2233. Sound interesting?
This is just step one: building a quartal stack from the root. But just like the case with "normal chords" built off of scales, we can go on to apply this formula to each additional note in the dorian mode, building a total of 7 quartal stacks from it. Continueing with E dorian, the result is the following series:
So now we have 7 four-note quartal stacks from E dorian. It could be a practise routine in and of itself to play these up and down the neck. Also, try to see what each of these sound like over an open E ringing out or a droning E note played by someone else. They all have an unique character when played against the root.
But things don't stop here. Just like how normal 7th chords have inversions, so do these quartal stacks. Indeed, the way things happen to work out, there are actually more inversions for quartal stacks than there are for 7th chords. So let's return to the first quartal stack built off of the root (xx2233) and see what we can do with it.
There is a simple formula that one can apply to invert this chord. Take whatever notes are at the bottom and top and reverse them, while keeping the middle two notes static. So the G at the top goes down to an E, and the E at the bottom goes up to a G. The result is this voicing: xx5230. Nice and dissonant!
Next step: find another arrangement of these same notes, building now from the G being at the bottom. The next voicing that one finds is this: xx5755. And we can then go on to apply the same formula that we did to the first voicing by reversing the top and bottom notes, which gives us: xx7753.
If we continue like this, this is the series of voicings that we end up with:
That's quite an interesting series of sounds all coming from the original quartal stack. Just like with the stacks we built from each note of the mode, it is of interest to hear what they sound like on top of a ringing open E or some kind of droning E. And a practise routine could be made out of transitioning between these inversions up and down the neck.
These are just the examples of what one can do with the dorian mode. The same concept and formulas can be applied to the other modes as well, with just as interesting results. Once you are reasonably used to running through these kind of voicings, it can be a great tool to make your own music with or when improvizing in modal music. Enjoy the new tools at your disposal!