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A7♯9

Character: gritty

  1. ARtriad
  2. C♯3triad
  3. E5triad
  4. G♭7add
  5. B♯♯9add
Open A7♯9 in the chord libraryDownload the A7♯9 chart (PDF)
Voicings

3 ways to play A7♯9

Every voicing sits inside one of the five CAGED shapes, low to high on the neck, with its octave doublings in grey.

  • Triad note
  • Substitute
  • Added
  • Anchored root
  • Bass
  • Doubling
CC shape Root position A7♯9
9 10 11 12 13 5 ♯9 ♭7 3 R 5

Frets x 12 11 12 13 0Notes A C♯ G B♯Intervals 1 3 ♭7 ♯9Base triadA major, root position

The ♭7th takes the 5th’s string. The ♯9th gets a string of its own.

GG shape Root position A7♯9
1 2 3 4 5 5 ♯9 ♭7 3 R

Frets 5 4 5 5 x xNotes A C♯ G B♯Intervals 1 3 ♭7 ♯9Base triadA major, root position

The ♭7th takes the 5th’s string. The ♯9th gets a string of its own.

EE shape Root position A7♯9
5 6 7 8 5 ♯9 ♭7 3 R R

Frets x 0 7 6 8 8Notes A C♯ G B♯Intervals 1 3 ♭7 ♯9Base triadA major, root position

The ♭7th takes the 5th’s string. The ♯9th gets a string of its own.

The rules

The construction rules A7♯9 follows

  1. Start from a triad

    Root, 3rd and 5th, stacked in thirds. The 3rd makes it major or minor; the 5th makes it diminished or augmented when it moves.

  2. A third on top makes a 7th chord

    A major 7th over a major triad is maj7, a ♭7 is a dominant 7. Over minor you get m7 or m(maj7); over diminished, m7♭5 or the °7, whose 7th is lowered twice.

  3. Keep stacking for extensions

    The 9th, 11th and 13th are the 2nd, 4th and 6th an octave up. Each one sits on the stack below it: a 9th chord holds a 7th, a 13th holds the 9th and 11th in theory.

  4. On guitar, something has to give

    Each extension takes the string of a triad note that matters less, usually the 5th, or gets a string of its own. The root and 3rd stay: they say what the chord is.

  5. Alter a dominant for tension

    Raise or lower the 5th or the 9th, or add a ♯11 or ♭13, and a dominant 7th pulls harder towards the next chord: G7♯9, G7♭9, G7♭13.

All the rules, with examples, in the guide to the chord library.

Dominant 7th ♯9 in every key

More chords on A

A7♯9 chord questions

What notes are in A7♯9?

A7♯9 is spelled A C♯ E G B♯: A is the root, C♯ is the 3rd, E is the 5th, G is the ♭7th, B♯ is the ♯9th.

What is the formula of A7♯9?

1 3 5 ♭7 ♯9. It is a A major triad with the ♭7th, ♯9th stacked on top.

How many ways can you play A7♯9 on guitar?

This page shows 3 voicings of A7♯9, filed under the five CAGED shapes and named by inversion, from the open position up to the 16th fret.