Formula
- Degrees: 1 2 b3 4 b5 b6 b7.
- Steps: W H W H W W W (2 1 2 1 2 2 2 semitones).
- Parent scale: 6th mode of melodic minor. A Locrian #2 = notes of C melodic minor from A: A B C D Eb F G.
- On C: C D Eb F Gb Ab Bb (from Eb melodic minor). On B: B C# D E F G A (from D melodic minor).
Alternative names: Locrian ♮2, Aeolian b5, “half-diminished scale”.
Characteristic note and color
It is Locrian with the major 2nd: it keeps the b5 (which makes the tonic a half-diminished chord) but removes the b2, which in Locrian creates a harsh minor 9th against the root. The color is melancholic and suspended but softer and more “singable” than Locrian. It is the quintessential jazz scale over the m7b5 (ø7) chord, with the natural 9th available as a tension (Aø9 = A C Eb G B).
Diatonic chords (C Locrian #2)
| Degree | Triad | Seventh |
|---|---|---|
| i° | C° | Cø7 |
| ii° | D° | Dø7 |
| biii | Ebm | Ebm(maj7) |
| iv | Fm | Fm7 |
| bV+ | Gb+ | Gbmaj7#5 |
| bVI | Ab | Ab7 |
| bVII | Bb | Bb7 |
Where it is used (chord-scale)
- iiø7 in a minor key: in the ii–V–i of G minor, Aø7 – D7alt – Gm. Over Aø7 you can play A Locrian (A Bb C D Eb F G, from the key) or A Locrian #2 (A B C D Eb F G): the B natural is the 9th, softer.
- viø7 of melodic minor and ø7 as a tonic chord in modal pieces or in film cues.
- m6 chord with the bass on the 6th: Cm6/A = Aø7, so the scale over Aø7 coincides with the melodic minor of C (see Sixth chords).
Quick comparison over the ø7 chord
| Scale over Aø7 | Notes | 9th | Color |
|---|---|---|---|
| A Locrian | A Bb C D Eb F G | b9 (Bb) | dark, tonal (from the natural minor of G) |
| A Locrian #2 | A B C D Eb F G | 9 (B) | soft, modern |
Super Locrian bb7 is not suitable, because it contains the diminished 7th (a °7 chord, not ø7). The choice depends on the melody and the context: if the melody has the Bb, use Locrian; if it is free, the #2 gives a more “open” sound.
Use in genres
- Jazz and bossa: minor ii–V–i in almost all standards (“Autumn Leaves”, “Blue Bossa”, “Alone Together”); the Aø9 voicing is common in modern jazz piano.
- Film music: ø9 chords as colors of suspension and melancholy (widely used in orchestral ballads).
- Neo-soul and lo-fi: the ø7 with a 9th as a “sad but soft” chord before a dominant.
Melodies
- The 9th (2) and the 11th (4) over the ø7 chord are the most beautiful tensions: over Aø7, B and D.
- A phrase that descends b7 – b6 – b5 – 4 – b3 (G F Eb D C over Aø7) prepares the dominant well.
Common mistakes
- Using the b2 (Bb) and the 2 (B) in the same passage over the same chord: pick one scale.
- Confusing the ø7 with the °7: the correct scale for the diminished chord with a diminished 7th is another (whole-half diminished or Super Locrian bb7).
- Playing the perfect 5th over a ø7: it is the note the chord excludes.
Exercise
- Loop Aø7 – D7alt – Gm(maj7) – Gm6: improvise over Aø7 first with A Locrian, then with A Locrian #2 and compare.
- 4-voice voicing of Aø9 without the root (C Eb G B) on a Rhodes: listen to how it sounds like a Cm(maj7).
- Write a 2-bar phrase over Dø7 – G7b9 – Cm using the natural 9th (E) over Dø7.
Connections
Melodic minor and its modes; Locrian mode; The jazz ii–V–I; Sixth chords; Chord-scale theory.