Scale degrees · A major
The 13 of A is F♯
The 13 (thirteen) of A is F♯ (F sharp): a major thirteenth above the root.
A — the root, 1F♯ — the 13
How to find it
A 13th is a 6th an octave up, so it takes the 6th's letter: A, B, C, D, E, F.
Then the sound: a major thirteenth is 21 semitones above A, and the F that is 21 semitones up is F♯.
That is why it is F♯ and not G♭: G♭ is the same key on the piano, but from A it would be a 14th, not a 13th.
Where you meet it
The 13 is the 6 an octave up: the top of a thirteenth chord, and of the classic dominant voicing with the 3 and the ♭7.
In A13:
A · C♯ · E · G · B · F♯
The 13 in every key
| Key | The 13 |
|---|---|
| C | A |
| G | E |
| D | B |
| A | F♯ |
| E | C♯ |
| B | G♯ |
| F♯ | D♯ |
| D♭ | B♭ |
| A♭ | F |
| E♭ | C |
| B♭ | G |
| F | D |
Every degree of A
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