Gb Altered Scale (Super Locrian Scale)

Gb – G – A – Bb – C – D – E – Gb
Formula:H-W-H-W-W-W-W
Scale Degrees:1-♭9(♭2)-#9(♭3)-3-#11(♭5)-♭13(♭6)-♭7-8

Introduction

The Gb Altered Scale is the 7th mode of the G Melodic Minor scale, used over Gb7alt chords. Its notes are Gb - G - A - Bb - C - D - E - Gb. Because Gb7 (enharmonically F#7) is the dominant of B/Cb, this scale resolves to Bmaj7 in jazz progressions. The Gb Altered Scale shares its note content with G Melodic Minor, so if you know G Melodic Minor you can find this scale instantly by starting on Gb.

Enharmonic equivalent: G♭ is enharmonically equivalent to F♯. See F# Altered Scale Scale.

Gb Altered Scale (Super Locrian Scale) Notes

DegreeNameNote
1TonicF#4
♭9(♭2)SupertonicG4
#9(♭3)MediantA4
3SubdominantA#4
#11(♭5)DominantC5
♭13(♭6)SubmediantD5
♭7Leading ToneE5
8OctaveF#5

Key Signature

The key of Gb Altered Scale has 6 flats: B♭, E♭, A♭, D♭, G♭, C♭.

BEADGC

Chords in the Key of Gb Altered Scale

These are the diatonic triads built on each degree of the Gb Altered Scale (Super Locrian Scale):

DegreeNumeralChordQuality
1IGb MajorMajor
2iiAb MinorMinor
3iiiBb MinorMinor
4IVB MajorMajor
5VDb MajorMajor
6viEb MinorMinor
7vii°F DiminishedDiminished

Gb Altered Scale (Super Locrian Scale) — Frequently Asked Questions

What notes are in the Gb Altered Scale?

The Gb Altered Scale contains seven notes: Gb G A Bb C D E (plus the octave). It is the 7th mode of the G Melodic Minor scale — playing G Melodic Minor starting on Gb produces the Gb Altered Scale. It contains all four possible alterations of a dominant chord: b9 (G), #9 (A), #11/b5 (C), and b13 (D).

What chord is the Gb Altered Scale used over?

The Gb Altered Scale is used almost exclusively over Gb7alt — a dominant 7th chord with alterations. It creates maximum harmonic tension before resolving to the tonic chord a fifth below. In a ii–V–I progression, the altered scale goes on the V chord (Gb7alt) to create powerful tension that resolves into the I chord.

What is the fastest way to find the Gb Altered Scale?

The shortcut: play G Melodic Minor starting on Gb. Every note of G Melodic Minor, starting from Gb, gives you the Gb Altered Scale. Once you know your melodic minor scales, finding any altered scale is immediate — just start the melodic minor from its 7th degree.

Why is the altered scale called "Super Locrian"?

The Gb Altered Scale is identical to the Locrian mode except it also lowers the 2nd degree (making it b2 / b9). This extra lowering gives it even more tension than Locrian, earning it the name "Super Locrian." The interval formula is H–W–H–W–W–W–W.

How does the Gb Altered Scale differ from the Gb Dominant 7th scale (Mixolydian)?

Gb Mixolydian (the standard dominant scale) uses the natural 2nd, 3rd, 5th, and 6th. The Gb Altered Scale alters all of these — the 2nd becomes b9 (G), the 3rd becomes #9 (A), the 5th becomes b5 (C), and the 6th becomes b13 (D). This maximises tension and is why jazz musicians call it the "altered" dominant.

What music uses the Gb Altered Scale?

The Gb Altered Scale is used in jazz improvisation, especially in bebop, post-bop, and fusion. It appears over altered dominant chords in ii–V–I progressions, turnarounds, and secondary dominants. Famous jazz pianists including Bill Evans, Herbie Hancock, and Brad Mehldau use altered scales extensively.

Practice Tips

  • Remember the shortcut: Gb Altered Scale = G Melodic Minor starting on Gb. Learn G Melodic Minor first if you haven't already.
  • Practice the scale slowly, listening for the tension created by the b9 (G), #9 (A), b5 (C), and b13 (D).
  • Play the Gb Altered Scale over a Gb7alt chord and resolve it to the tonic chord a fifth below — feel the tension-release that defines altered dominant harmony.
  • Use 3-4 note fragments rather than running the full scale — jazz phrasing uses small motifs, not scale runs.
  • Target the major 3rd and b7 of the Gb7alt chord as anchor tones; use the altered tensions (b9, #9, b13) as colour around them.
  • Listen to jazz recordings and identify when altered scales are used — the tense, "outside" sound before resolution is characteristic.