Locrian: A Not-So-Scary Approach to the Leading Tone Mode (Part 1 of 2)

How to treat Locrian as a harmonic driving force instead of a sour set of notes.

QUICK SIDE NOTE: I have so much to talk about regarding the Locrian mode that I’ve divided it up into two articles, which both with go out on Jan. 1st and 2nd of 2023. Thanks for reading!

What is Locrian?

When it comes to musical scale and modes the Locrian mode is unique in the way it tends to drive people away from its sound. Locrian is the seventh mode of the Major Scale. This mode has been called scary, evil, and all kinds of other negative terms. It also has a very dissonant sound that is derived from the TriTone interval found in Locrian's diminished structure. Unlike other modes that can be played by themselves to create great melodies, the Locrian mode generates melodies that remain unresolved. This makes using Locrian a challenge for most people. There are videos on the internet that try to show how the Locrian mode can sound good, but a lot of them tend to use the functionality of minor modes in order to make Locrian more palatable.

So why even both with this mode? Well, Locrian is incredibly useful once you know how to use it as a "Leading Tone Mode." The first degree note of Locrian is the Leading Tone of the Major Scale. If we play a melody using Locrian with the intent of leading up to Ionian or down to Aeolian, then we can use a dissonant melody that resolves into another mode.

Leading to Ionian and Aeolian

B Locrian uses the notes B, C, D, E, F, G, & A and naturally creates a Half-Diminished structure using degrees 1, b3, b5, and b7. The note B is right between the Natural Minor and Major scale notes of A and C. Bm7b5 resolves to C major and A minor perfectly for many reasons but look at how C major is nested inside of Bm7b5. Now take C major and include the note A in the bass and you get Am7. Our Locrian chords like to resolve to the notes that are not part of degrees 1, b3, and b5 which make a diminished triad.

In the key of C our Locrian chord is Bm7b5, aka B Half-Diminished. This structure sits a half-step below our Ionian chord of CMaj7 and a whole step above our Aeolian chord of Am7. Ionian and Aeolian are our main major and minor modes that we use for a variety of reasons. Without spending too much time outside of Locrian, think of Ionian and Aeolian as structures that help us to easily create melodies. The other modes are just as useful but have tension notes. Dorian has a natural sixth degree, Phrygian has a flattened second degree, Lydian has the sharpened fourth degree, and Mixolydian has a flattened seventh degree. Ionian and Aeolian have their own tensions which line up with Locrian as an easy way to resolve most tensions. The way we do this is by using "Functional Harmony".

Think of the flow of chords in these charts like a rubber band. We start anywhere and stretch out from Tonic towards Dominant while either easing back or snaping back to Tonic. We can also wobble between the three groups of chords or stay in one group as long as we like. The point of this isn’t to jump all over, but to find a “flow” that helps to describe your song.

Using Functional Harmony, we can start in C Ionian or A Aeolian and use CMaj7 or Am7 as a Tonic chord. We can do anything we want to move from a Tonic chord to a Pre-Dominant chord followed by a Dominant chord. We can also skip the Pre-Dominants and go straight to Dominant. It’s the Dominant chords that help us return to Tonic and Locrian provides a great way to come back to Tonic.

Think of Locrian's high dissonant structure as a way of ramping up the tension so we can release it back to Tonic. We can do this by playing a Locrian chord like Bm7b5 and then resolving to a Tonic chord. We can also play a Bm7b5 arpeggio or a Locrian melody. Any of these options are guaranteed to help you create a strong Ionian or Aeolian resolution. Check out these audio examples of B Locrian leading to C Ionian and A Aeolian.

These two progressions use our Locrian chord of Bm7b5 to resolve to either C Ionian or A Aeolian. Both of them use a Tonic chord, followed by a Pre-Dominant chord, then our Dominant Locrian chord resolves back to Tonic.

Secondary Diminished to Dorian, Phrygian, Lydian, and Mixolydian

We can continue to use Locrian for its Dominant functionality for the other modes. Sticking to the key of C we have D Dorian, E Phrygian, F Lydian, and G Mixolydian. Our B Locrian structures do not go to any of these modes because the major modes are not a half-step above B Locrian and the minor modes are not a whole step below B Locrian.

The m7b5 chord leads a whole step down to a minor or up a half-step to a major. We can use this concept to add in Secondary Diminished chords that lead down a whole step to Dm or Em and up a half-step to F or G.

What we can do is use a Secondary Diminished structure. This is when we use a diminished structure like Locrian outside of the key we are currently in. These non-diatonic chords still work and help lead us to where we want to go. E Locrian is a half-step down from F Lydian, so we can use an Em7b5 to lead to FMaj7. We can do the same thing with A#m7b5 leading up to a Mixolydian G7 chord. To move to our minor modes, we can use Em7b5 again to lead to Dm7 for a Dorian resolution. To get to E Phrygian we can use F#m7b5 before it and move down a whole step to Em7.

Whenever we use a Secondary Diminished chord, our listener will hear it as if we are going to Ionian or Aeolian simply due to how Locrian sits between Ionian and Aeolian.

When we use a m7b5 to move to a major or minor, the major chord will sound Ionian and the minor chord will sound Aeolian unless you play notes that belong to a different mode. So, playing chords in the key of C and then F#m7b5 to G will imply that the G could be a GMaj7 (G, B, D, F#), but if you play G7 (G, B, D, F) then you won’t leave the key by using the note F. The only other option to stay in the key of C is to use the chords C and Am since they are in all three keys shown above.

To keep this from happening we simply need to play a note that gives us a key interval of the mode we are actually in.

The two Blues scales are pentatonic scales that work with any of our major or minor modes because the degrees used line up. To make a chord sound like it comes from a mode, we need to play a note that is NOT from either of the Blues scales. This way we can make the chord sound distinct. Playing Em7b5 up to FMaj7 make the F chord sound Ionian, so play the Lydian #4 note in FMaj7 (which is B) to keep this chord from sounding like it is Ionian.

Using the charts above we can play a m7b5 chord a whole step above D Dorian or E Phrygian before moving to either Dm7 or Em7. D Dorian is the only minor mode with a natural sixth degree, so playing this degree will keep it from sounding like Aeolian. Similarly, we can use the flattened second degree in Phrygian to keep that structure from sounding like Aeolian. Check out the audio clip below where I'll play Em7b5 to Dm7 three different ways. I'll use Em7b5 to D Aeolian, Em7b5 to D Dorian, and then Em7b5 to D Phrygian so you can hear how playing just a few notes that are only found in each minor mode help to keep your listener grounded in the sound you want to use.

We can also use Em7b5 and move up a half-step to either Lydian or Mixolydian. This time we'll use Lydian's sharpened fourth degree and Mixolydian's flattened seventh degree to keep our major sound from being perceived as Ionian, which has a natural fourth and seventh degree. In the next audio example, I'll use Em7b5 to FMaj7 in Lydian. Em7b5 comes from the Key of F, while a Lydian F chord comes from the key of C. I’ll take a few chords from the first key and lead up to Em7b5 so that you can hear F Lydian come through in a new key.

Pairing with Mixolydian

So far we've been using Locrian as it is in order to move toward any other mode in a variety of ways. Another great way to use the Locrian sound is blend it into Mixolydian. In most applications you'll find that the Mixolydian Dominant Seven chord and Locrian Half-Diminished chord act as Dominant chords, which usually lead to a Tonic chord.

The TriTone interval is what creates the tension in both a Dominant Seven and Half-Diminished chord.

If we play a B Diminished triad (notes are B, D, and F) we have a B Locrian chord, but if we simply add in a G note to the bass end, we get G7 (notes are G, B, D, and F) which is a G Mixolydian chord. We can do the same with Bm7b5 and add a G note to the bass to get a Bm7b5/G, which is the same thing as a G9 chord. By simply taking a B Locrian chord or melody and moving the Tonic note of B down two whole steps to G allows us to change the context of which Dominant structure we are using.

The same can be done with G Mixolydian. We can play a Mixolydian chord or melody and by treating B as the Tonic for a moment we can then use F as B's flattened fifth degree note. This transformation of Mixolydian to Locrian will increase the tension before returning to a Tonic. Another way to think of this us that a TriTone interval that uses the root note (Bm7b5) has higher tension than a TriTone interval set above the root note (G7).