The notes
- A1
- C♯3
- E♯♯5
The A augmented arpeggio is A, C♯, E♯.
You may also see it called 1 3 ♯5.
On the staff
On a bass staff, the A augmented arpeggio is written A C♯ E♯.
The solid notes are the A augmented arpeggio. The pale notes are the rest of A harmonic minor, the larger scale it is carved out of, so you can see which notes it leaves out.
Why the A augmented arpeggio has these sharps
- A1
- 4
- C♯3
- 4
- E♯♯5
- 4
- A8
A scale is a pattern of steps, and this one is 4 4 4: 4, 4, 4, and so on. 4 stands for a step of four semitones. The pattern is what gives A augmented its sound, and it stays the same whichever note you start on.
This scale has only three notes, so it does not use every letter. It is built on A harmonic minor, and the notes it shares are spelled the same way as they are there.
The pattern still does not fit the plain letters. If you walk the pattern up from A, two letters cannot keep up:
- C♯ — the third. The pattern needs 4 from A, but A to C is only a tone and a half, so C has to rise to C♯.
- E♯ — the sharp fifth. The pattern needs 4 from C♯, but C♯ to E is only a tone and a half, so E has to rise to E♯.
None of those accidentals was a choice. Once you pick the note to start on, the pattern decides the rest, and a key signature is a record of the result.
The A augmented arpeggio is written with C♯ and E♯, because the 4 4 4 pattern of steps cannot be spelled with plain letters from A.
The pattern of steps is the part of a scale that never changes. The letter names take sharps or flats to fit that pattern, and a key signature is a record of those sharps or flats.
On the piano
The keyboard shows the same three notes as a shape you can see. The coloured keys are the A augmented arpeggio, the pale keys are the rest of A harmonic minor, and you can click any key to hear it.
A augmented arpeggio on the whole neck
27 notes of the A augmented arpeggio are marked across five strings.
This is every place the notes of the A augmented arpeggio fall on the 5-string bass, with each note's name and its scale degree. The roots are marked so you can find your bearings.
Position by position
The A augmented arpeggio has three playable positions, at frets 2–6, 6–10 and 10–14.
Each shape starts on a different degree of the scale and fits inside five frets, so your hand can play all of it without moving.
One climb up the neck
The climb runs from fret 10 to fret 20 and plays seven notes.
This is one path from the lowest root to the top of the neck, and it plays each note once, never on two strings. It takes a different number of notes on different strings. The widest stretch on any one string is four frets.