Locrian Harmony?

Question

I like utilizing modes in my the pieces I write, but there is one mode I've never been able to fully grasp and utilize and that is the Locrian mode.The chords that naturally occur in the Locrian mode don't seem to lend themselves well to any chord progression that implies the tonic especially since the tonic chord itself is diminished and is perceived by most to be unstable. So when composing in the Locrian mode, is it possible to create a chord progression that leads back to the tonic convincingly and if so what are the concepts behind it and what should one look for?

Answer 1

Locrian can be tricky to get right, but it is feasible to get something going in the mode. There are ways to hide that instability, but it's personal preference whether you consider it cheating or not.

Since the vii diminished often shows up in first inversion in classical voice leading, you might find it useful to spell the chord that way (so with no accidentals in the key signature you'd play Bdim as D-F-B). You can further hide the instability by making that a 7th chord and removing the diminished 5th all together, though in inversion, it might have more of a flavor of a major 6 chord as seen in jazz, but with no 3rd (D-A-B). This runs the risk of sounding dorian if you don't strongly emphasize B as scale degree 1 in the melody.

The option of playing the 7th chord without the 5th is still there, which would trick the ear into thinking it was a minor 7th chord. In that case, it would feel like phrygian with limitations (or opportunities if you're an optimist).

In terms of resolution, that tritone between the bass in chords i and V make a typical dominant resolution unfeasible and unsatisfying. If you don't want to add accidentals and keep this strictly modal, you might want to try plagal resolutions using chords in the subdominant positions like II and iv, which would be the same subdominants in a phrygian composition.

There's also the factor that if you think about your key it in terms of a minor blues mode, that flat 5 is right at home as an embellishment. So in theory, a jazzy/bluesy composition might be a good fit for this mode.

Other than that, a good ol' drone with your locrian scale degree 1 throughout a piece can give it some auditory stability if you want to go in more of an exotic direction.