Learn the Super Locrian ♭♭7 Mode
Extremely dark and dissonant. almost atonal. With nearly every note flatted (including the bb7), it sounds like music dissolving at the edges. Diminished in character, tense, and inherently unstable.
Try Super Locrian ♭♭7 interactivelyWhat makes it sound this way
The b4 (enharmonically a major 3rd) and bb7 (enharmonically a 6th) are the defining oddities. Nearly every degree is flatted, including a double-flat 7th, making this the most extreme and dissonant mode in the standard 21-mode collection.
Overview
Super Locrian bb7, also called Ultralocrian, is the seventh mode of the harmonic minor scale and the most dissonant mode in the standard 21-mode collection. It flattens nearly every degree. including a double-flat 7th (enharmonically a 6th). It exists because harmonic minor has seven modes and this is the last one; in practice, it is almost never used as an improvisation scale.
Why it sounds the way it does
With 1-b2-b3-b4-b5-b6-bb7, there is almost no consonance against the root. The bb7 (enharmonically a major 6th) does not function as a 7th in any practical sense, which makes harmonic analysis confusing. The b4 (enharmonically a major 3rd) blurs the line between diminished and dominant function. The overall effect is extreme darkness and instability. a mode that exists at the very edge of tonal coherence.
Chord fit
It theoretically serves diminished 7th chords, but in practice, every jazz and classical player uses the symmetric diminished scale (half-whole or whole-half) over dim7 chords instead. The diminished scale is easier to finger, sounds better melodically, and has useful symmetrical properties. Super Locrian bb7 is an answer to a question nobody is asking in a performance context.
Practical improvisation use
This is the honest truth: you will almost certainly never deliberately play Super Locrian bb7 in a performance. It is a theoretical artifact of the harmonic minor system. Knowing it exists demonstrates complete understanding of harmonic minor modes, and that understanding IS valuable. but the mode itself is not a practical tool.
Guitar practice angle
If you can play all seven modes of harmonic minor in sequence across the neck and name each one, you have reached a level of modal fluency that will serve you well. Super Locrian bb7 is the seventh stop on that journey. Practice it as the endpoint of a harmonic minor mode marathon, not as a standalone scale.
Compare it to...
The Altered scale (7th mode of melodic minor) is also extremely tense but is enormously practical over altered dominant chords. Standard Locrian has a b5 and b2 but maintains a recognizable half-diminished function. Super Locrian bb7 pushes beyond both into near-atonal territory.
What to listen for
Play the scale slowly and notice how every note creates friction against the root. There is no resting point, no consonance. That total tension is the sound of harmonic minor's most extreme mode. Compare it against the Altered scale. which has similar levels of tension but over a DOMINANT chord, giving it a functional purpose that Super Locrian bb7 lacks.
Practice suggestion
Use this as the capstone of a harmonic minor mode drill. Play B Super Locrian bb7 (C harmonic minor from B), then resolve to C harmonic minor. The relief of arriving on the tonic mode after the tension of the seventh mode is the entire lesson. hearing how the same seven notes can range from stable (mode 1) to extreme (mode 7) depending on the root.
When to reach for it
- •Theoretical understanding of harmonic minor modes
- •Over diminished 7th chords (rarely. diminished scales are preferred)
- •Extreme tension and dissonance in composition
- •Complete harmonic minor analysis
On the fretboard
- •Map it from the 7th degree of harmonic minor shapes: it is the last mode in the sequence
- •If you want to play over diminished chords, learn the diminished scale (half-whole or whole-half) instead. it is far more practical
- •Use this mode as a theoretical endpoint: understanding it proves you have fully absorbed harmonic minor
Common mistakes
- •Spending practice time on this mode before mastering the foundational 12-15 modes
- •Trying to use it over diminished chords in performance when the diminished scale is always better
- •Confusing it with the Altered scale. similar levels of tension but different functions and parent scales
Test yourself
If you can answer these in your own words, you have the concept. If not, revisit the sections above.
- Why is Super Locrian bb7 impractical for most performance situations?
- What scale do most players actually use over diminished 7th chords?
- Which harmonic minor key generates B Super Locrian bb7?