Altered chords

Altered chords, or alterations, means that a note in the chord is altered. For example, a flattened fifth in a C9 chord would result in a C9b5. This can be illustrated in the following comparison:

  • C9: C E G Bb D
  • C9b5: C E Gb Bb D

Alterations also involve sharpen notes, as in C9#5. Once again can the alteration be illustrated by a comparison:

  • C9: C E G Bb D
  • C9#5: C E G# Bb D

The following will look closer on some altered chord categories:

Movable altered chords

C9b5

  • C9b5 chord diagram

C9#5

  • C9#5 chord diagram

C13b5

  • C13b5 chord diagram

Cm#5

  • Cm#5 chord diagram

The chord names

The flatted tone is sometimes marked with a minus sign instead of the flat sign: C7-5. They are also often written partly in parenthesis, marking the alternating part of the chord: C7(b5).

The sharpened tone is sometimes marked with a plus sign instead of the flat sign: C7+5.

Theory and progressions

Altered chords are most used in jazz. Notice that these chords tend to be atonal (use notes outside the key). They are often used as passing chords or substitutions. This will be illustrated with two chord progressions:

Using an altered chord as a passing chord can be made by placing it directly before or after its non-altered version and both are often played in in measure:

Bm7 - E7 - E7b9 - Amaj7

Using an altered chord as a substitution can be made by replacing its non-altered version with it:

Bm7 - E7b9 - Amaj7 (instead of Bm7 - E7 - Amaj7)

Back to chord types

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