Explore scales · Bass
B♭ altered scale on bass guitar
B♭ altered contains B♭, C♭, D♭, E♭♭, F♭, G♭, and A♭. Box 2 keeps the root on string 4, fret 6 for a mid-neck altered run.
How it is built
Formula 1, ♭2, ♭3, ♭4, ♭5, ♭6, ♭7
How do you play the B♭ altered scale on bass?
B♭ altered in box 1 runs from fret 0 to fret 3, 8 notes across 4 strings, from F♭ on the E string at fret 0 up to B♭ on the G string at fret 3. 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 |
|---|---|---|
| 4 (E) | 0, 2 | F♭, G♭ |
| 3 (A) | 1, 2 | B♭, C♭ |
| 2 (D) | 0, 2 | E♭♭, F♭ |
| 1 (G) | 1, 3 | A♭, B♭ |
Box 2 · frets 2–5
B♭ altered in box 2 runs from fret 2 to fret 5, 9 notes across 4 strings, from G♭ on the E string at fret 2 up to C♭ on the G 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 |
|---|---|---|
| 4 (E) | 2, 4 | G♭, A♭ |
| 3 (A) | 2, 4, 5 | C♭, D♭, E♭♭ |
| 2 (D) | 2, 4 | F♭, G♭ |
| 1 (G) | 3, 4 | B♭, C♭ |
Box 3 · frets 4–7
B♭ altered in box 3 runs from fret 4 to fret 7, 11 notes across 4 strings, from A♭ on the E string at fret 4 up to E♭♭ on the G string at fret 7. The root falls on the E string at fret 6.
Every note in this box, string by string
| String | Frets | Notes |
|---|---|---|
| 4 (E) | 4, 6, 7 | A♭, B♭, C♭ |
| 3 (A) | 4, 5, 7 | D♭, E♭♭, F♭ |
| 2 (D) | 4, 6 | G♭, A♭ |
| 1 (G) | 4, 6, 7 | C♭, D♭, E♭♭ |
Box 4 · frets 6–9
B♭ altered in box 4 runs from fret 6 to fret 9, 11 notes across 4 strings, from B♭ on the E string at fret 6 up to F♭ on the G string at fret 9. The root falls on the E string at fret 6 and the D string at fret 8.
Every note in this box, string by string
| String | Frets | Notes |
|---|---|---|
| 4 (E) | 6, 7, 9 | B♭, C♭, D♭ |
| 3 (A) | 7, 9 | F♭, G♭ |
| 2 (D) | 6, 8, 9 | A♭, B♭, C♭ |
| 1 (G) | 6, 7, 9 | D♭, E♭♭, F♭ |
Box 5 · frets 9–12
B♭ altered in box 5 runs from fret 9 to fret 12, 10 notes across 4 strings, from D♭ on the E string at fret 9 up to G♭ on the G string at fret 11. No root falls inside this box; it sits between two of them.
Every note in this box, string by string
| String | Frets | Notes |
|---|---|---|
| 4 (E) | 9, 10, 12 | D♭, E♭♭, F♭ |
| 3 (A) | 9, 11 | G♭, A♭ |
| 2 (D) | 9, 11, 12 | C♭, D♭, E♭♭ |
| 1 (G) | 9, 11 | F♭, G♭ |
Why it sounds like that
B♭ altered lowers the fourth of B♭ locrian to E♭♭, producing 1, ♭2, ♭3, ♭4, ♭5, ♭6, ♭7. The tritone sits between B♭ and F♭. See B♭ locrian for the unaltered fourth.
When to use it
B♭ altered fits B♭ 7th flat 5 and B♭ 7th sharp 5 chords. Use it over B♭ 7th flat 5 in bebop or modern jazz. The ♭2 and ♭6 create strong dominant tension.
Which position to practise
Practise Box 2 first. The root on string 4, fret 6 gives access to the scale across four frets without shifting.
Common questions
What notes are in B♭ altered?
B♭ altered contains B♭, C♭, D♭, E♭♭, F♭, G♭, and A♭. The scale degrees are 1, ♭2, ♭3, ♭4, ♭5, ♭6, ♭7. It is also spelled A♯ in enharmonic notation for the same sounding root.
Which chords does B♭ altered fit?
B♭ altered fits B♭ 7th flat 5 and B♭ 7th sharp 5 chords. The scale works over dominant chords with altered fifths. Use it for bebop or modern jazz.
How does B♭ altered differ from B♭ locrian?
B♭ altered lowers the fourth degree from E♭ to E♭♭. This creates a ♭4 interval instead of a perfect fourth. The rest of the scale matches B♭ locrian.