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B♭ altered scale on guitar
B♭ altered uses B♭, C♭, D♭, E♭♭, F♭, G♭, A♭. Its double-flat fourth makes Box 2 a clear path to the altered tensions.
How it is built
Formula 1, ♭2, ♭3, ♭4, ♭5, ♭6, ♭7
How do you play the B♭ altered scale on guitar?
B♭ altered in box 1 runs from fret 0 to fret 3, 13 notes across 6 strings, from F♭ on the low E string at fret 0 up to G♭ on the high e string at fret 2. The root falls on the A string at fret 1 and the G string at fret 3.
Every note in this box, string by string
| String | Frets | Notes |
|---|---|---|
| 6 (E) | 0, 2 | F♭, G♭ |
| 5 (A) | 1, 2 | B♭, C♭ |
| 4 (D) | 0, 2 | E♭♭, F♭ |
| 3 (G) | 1, 3 | A♭, B♭ |
| 2 (B) | 0, 2, 3 | C♭, D♭, E♭♭ |
| 1 (e) | 0, 2 | F♭, G♭ |
Box 2 · frets 2–5
B♭ altered in box 2 runs from fret 2 to fret 5, 14 notes across 6 strings, from G♭ on the low E string at fret 2 up to A♭ on the high e string at fret 4. The root falls on the G string at fret 3.
Every note in this box, string by string
| String | Frets | Notes |
|---|---|---|
| 6 (E) | 2, 4 | G♭, A♭ |
| 5 (A) | 2, 4, 5 | C♭, D♭, E♭♭ |
| 4 (D) | 2, 4 | F♭, G♭ |
| 3 (G) | 3, 4 | B♭, C♭ |
| 2 (B) | 2, 3, 5 | D♭, E♭♭, F♭ |
| 1 (e) | 2, 4 | G♭, A♭ |
Box 3 · frets 4–7
B♭ altered in box 3 runs from fret 4 to fret 7, 16 notes across 6 strings, from A♭ on the low E string at fret 4 up to C♭ on the high e string at fret 7. The root falls on the low E string at fret 6 and the high e string at fret 6.
Every note in this box, string by string
| String | Frets | Notes |
|---|---|---|
| 6 (E) | 4, 6, 7 | A♭, B♭, C♭ |
| 5 (A) | 4, 5, 7 | D♭, E♭♭, F♭ |
| 4 (D) | 4, 6 | G♭, A♭ |
| 3 (G) | 4, 6, 7 | C♭, D♭, E♭♭ |
| 2 (B) | 5, 7 | F♭, G♭ |
| 1 (e) | 4, 6, 7 | A♭, B♭, C♭ |
Box 4 · frets 6–9
B♭ altered in box 4 runs from fret 6 to fret 9, 16 notes across 6 strings, from B♭ on the low E string at fret 6 up to D♭ on the high e string at fret 9. The root falls on the low E string at fret 6, the D string at fret 8 and the high e string at fret 6.
Every note in this box, string by string
| String | Frets | Notes |
|---|---|---|
| 6 (E) | 6, 7, 9 | B♭, C♭, D♭ |
| 5 (A) | 7, 9 | F♭, G♭ |
| 4 (D) | 6, 8, 9 | A♭, B♭, C♭ |
| 3 (G) | 6, 7, 9 | D♭, E♭♭, F♭ |
| 2 (B) | 7, 9 | G♭, A♭ |
| 1 (e) | 6, 7, 9 | B♭, C♭, D♭ |
Box 5 · frets 9–12
B♭ altered in box 5 runs from fret 9 to fret 12, 16 notes across 6 strings, from D♭ on the low E string at fret 9 up to F♭ on the high e string at fret 12. The root falls on the B string at fret 11.
Every note in this box, string by string
| String | Frets | Notes |
|---|---|---|
| 6 (E) | 9, 10, 12 | D♭, E♭♭, F♭ |
| 5 (A) | 9, 11 | G♭, A♭ |
| 4 (D) | 9, 11, 12 | C♭, D♭, E♭♭ |
| 3 (G) | 9, 11 | F♭, G♭ |
| 2 (B) | 9, 11, 12 | A♭, B♭, C♭ |
| 1 (e) | 9, 10, 12 | D♭, E♭♭, F♭ |
Why it sounds like that
B♭ altered is the seventh mode of C♭ melodic minor. The scale spells 1, ♭2, ♭3, ♭4, ♭5, ♭6, ♭7, with E♭♭ as the ♭4 and F♭ as the ♭5. Compared with B♭ locrian, the fourth drops from E♭ to E♭♭. The pattern H, W, H, W, W, W, W keeps half steps at the start and middle.
When to use it
Use B♭ altered over B♭7♭5 or B♭7♯5 chords in jazz, fusion, and bebop. It fits dominant chords that resolve to E♭ minor or E♭ major. The altered fifths and ninths add tension before a ii–V–I in E♭. Try it over B♭ 7th flat 5 or B♭ 7th sharp 5.
Which position to practise
Practise Box 2 first. It places the root on string 6, fret 6 and covers frets 2–5, giving easy access to the double-flat fourth on string 5.
Common questions
What notes are in B♭ altered?
B♭ altered contains B♭, C♭, D♭, E♭♭, F♭, G♭, and A♭. The formula is 1, ♭2, ♭3, ♭4, ♭5, ♭6, ♭7. It is the seventh mode of C♭ melodic minor. It is also spelled A♯ in enharmonic notation for the same sounding root.
Which chords does B♭ altered fit?
B♭ altered fits dominant chords with altered fifths, such as B♭7♭5 and B♭7♯5. It also works over B♭7♭9 and B♭7♯9. These chords typically resolve to E♭ minor or E♭ major.
How does B♭ altered differ from B♭ locrian?
B♭ altered has a flattened fourth (E♭♭) while B♭ locrian has a perfect fourth (E♭). The rest of the notes are identical. This single change makes altered sound more dissonant.
What is the step pattern for B♭ altered?
The step pattern is H, W, H, W, W, W, W. Starting on B♭, that gives B♭–C♭–D♭–E♭♭–F♭–G♭–A♭. The half steps fall between the first two and third and fourth degrees.