Formula
- Degrees: 1 b2 b3 b4 b5 b6 bb7.
- Steps: S T S T T S 1½ (1 2 1 2 2 1 3 semitones).
- Parent scale: 7th mode of harmonic minor. G# Super Locrian bb7 = notes of A harmonic minor starting on G#: G# A B C D E F.
- On C: C Db Eb Fb Gb Ab Bbb (from Db harmonic minor; in practical spelling C Db Eb E Gb Ab A). On B: B C D Eb F G Ab (from C harmonic minor).
Alternative names: ultra Locrian, altered bb7, “diminished Super Locrian”.
Characteristic note and color
It is the altered (Super Locrian) scale with the diminished 7th (bb7) in place of the minor 7th. It contains a full diminished seventh chord on the tonic (1 b3 b5 bb7: G# B D F) plus three tension notes (b2, b4 = enharmonic major 3rd, b6). Color: dark, tense, “one step from the tonic”: it is the leading tone waiting to rise.
Diatonic chords (G# Super Locrian bb7)
| Degree | Triad | Seventh |
|---|---|---|
| i° | G#° | G#°7 |
| bii | Am | Am(maj7) |
| biii° | B° | Bø7 |
| bIV+ | C+ | Cmaj7#5 |
| bv | Dm | Dm7 |
| bVI | E | E7 |
| bbVII | F | Fmaj7 |
(These are the chords of A harmonic minor seen from G#.)
Where it is used (chord-scale)
- vii°7 of a minor key: in A minor, G#°7 → Am. Over G#°7 the scale of the key is precisely G# Super Locrian bb7 (that is, A harmonic minor): the notes A, C and E (b2, b4, b6 relative to G#) are the notes of the target chord Am, already present as tensions.
- vii°7/V and passing diminished chords when you want to stay inside the minor key.
Alternative: over the diminished seventh many jazz players use the whole-half diminished scale (G# A# B C# D E F G), which adds symmetrical tensions. Super Locrian bb7 sounds more “tonal”, the diminished scale more “modern”.
Use in genres
- Baroque and Classical: all minor cadences with vii°7 – i (Bach, Mozart, Beethoven). The fast scales that start from the leading tone in virtuosic cadences are often, in effect, this mode.
- Neoclassical metal: diminished seventh arpeggios with harmonic minor passing notes (Yngwie Malmsteen, Jason Becker).
- Film music: suspense, waiting before a resolution to a minor tonic.
- Jazz: as a “key” scale over the diminished chord in a harmonic minor context.
Melodies
- The phrase 1 – b2 – b3 (G# – A – B) rises toward the target tonic; bb7 – b6 – b5 – 1 (F – E – D – G#) is a typical chromatic-diatonic descent.
- Using b2 (A) as an anticipated arrival note is the most “tonal” gesture.
Common mistakes
- Using it over a ø7 chord (with a minor 7th): there the bb7 clashes.
- Not recognizing that it is simply harmonic minor from the leading tone: thinking of it that way simplifies everything.
- Writing the notes with inconsistent spellings: in the score use the letters of the minor key (G# A B C D E F in A minor).
Exercise
- Cadence Am – Dm – G#°7 – Am: over G#°7 improvise with the notes of A harmonic minor starting from G#.
- Compare, over the same G#°7, the diminished scale (G# A# B C# D E F G) and Super Locrian bb7.
- Write a diminished seventh arpeggio with harmonic passing notes in the neoclassical manner, at 150 BPM in sixteenth notes.
Related
Harmonic minor and its modes; Altered scale; Diminished seventh chord and its uses; Diminished scale; Chord-scale theory.