Ab Locrian Mode
Ab–A–Cb–Db–D–Fb–Gb · root also written G#
Ab Locrian is the 7th mode of the A major scale: Ab–A–Cb–Db–D–Fb–Gb. Its character: unstable, dissonant, and eerie — the darkest of all modes.
The flat 2nd and flat 5th create a diminished root chord, making the tonic feel inherently unresolved. Used sparingly for maximum tension and unease. On guitar, target the flat 5th (D) in your phrases — landing on it against the root is what makes a line sound Locrian instead of plain minor.
Because every mode of A major shares the same seven notes, any A major fretboard shape works for Ab Locrian — what changes is the note you resolve to. Loop a Ab° vamp or a backing track that stays on Ab, keep resolving your phrases to Ab, and the Locrian color comes through. You'll hear this sound in metal and jazz.
Ab Locrian is mode 7 of A Major — same seven notes, resolved to Ab instead.
Ab Locrian on the Fretboard
Standard tuning, frets 0–12. Every dot is a note in the mode — blue dots are the root (Ab).
Notes and Intervals
| Interval | R | ♭2 | ♭3 | 4 | ♭5 | ♭6 | ♭7 |
|---|---|---|---|---|---|---|---|
| Note | Ab | A | Cb | Db | D | Fb | Gb |
The highlighted D is the flat 5th — the note that gives Locrian its sound.
Locrian vs. Natural Minor
Everything else about the two scales is identical — these are the only degrees that change.
| Ab natural minor | Ab Locrian | Note |
|---|---|---|
| 2 | ♭2 | A |
| 5 | ♭5 | D |
Chords in Ab Locrian
The seven chords of A Major, reordered to start from Ab — vamping between the first two or three keeps the Locrian sound from collapsing back into the parent key.
Songs That Use the Locrian Sound
Black Sabbath — “Black Sabbath”
The tritone (flat 5th) that opens the song captures Locrian's essence. Tony Iommi leans into the diminished quality for maximum dread.
Dream Theater — “The Glass Prison”
Uses Locrian passages in the heavy sections, leveraging the diminished root chord and flat 5th for intense, unsettled riffing.
John Coltrane — “Impressions (bridge)”
While primarily Dorian, Coltrane explores Locrian territory in his improvisations over half-diminished chords, pushing into its dissonant character.
Ab Locrian Mode FAQ
What is the Ab Locrian mode?
Ab Locrian is the 7th mode of the A major scale — the same seven notes starting from Ab: Ab–A–Cb–Db–D–Fb–Gb. The interval formula is R–♭2–♭3–4–♭5–♭6–♭7.
What is the difference between Ab Locrian and Ab natural minor?
Two notes: where Ab natural minor has 2, Ab Locrian has ♭2 (A), and where Ab natural minor has 5, Ab Locrian has ♭5 (D). Those alterations are the entire difference in sound — everything else about the two scales is identical.
What chords work with Ab Locrian?
The seven chords of the parent A major scale, reordered to start from Ab: Ab° (i°), A (♭II), Bm (♭iii), Dbm (iv), D (♭V), E (♭VI), F#m (♭vii). A two-chord vamp between Ab° and A is the classic way to establish the Locrian sound without drifting back to the parent key.
What major scale has the same notes as Ab Locrian?
A major. Ab Locrian uses exactly the notes of A major starting from its 7th degree, so every A major shape on the fretboard doubles as a Ab Locrian shape. The same notes also spell A Ionian, B Dorian, Db Phrygian, D Lydian, E Mixolydian, and F# Aeolian.
How do I practice the Ab Locrian mode?
Modes live and die by harmonic context — run over a static Ab° vamp or a drone on Ab, not a full progression that pulls back to the parent key. Play the A major shapes you already know, resolve every phrase to Ab, and lean on the flat 5th (D). OpenFret's free Studio has a fretboard viewer and metronome for exactly this, and Guitar Quest turns scale practice into a game with real-time pitch detection.
Modes Sharing These Notes
All seven modes of A Major use the same seven notes — each one treats a different note as home.
Related Modes
Practice Ab Locrian with real feedback
Guitar Quest listens to your real guitar and turns scale practice into a game — run modes to battle monsters, with every note checked by pitch detection. Free in your browser, no signup needed.