Diminished

Diminished seventh chords

Symmetrical chord: C-Eb-Gb-A (double flat 7). Formula: 1-b3-b5-bb7. Repeats every minor 3rd.

In every key

The same shape, moved. The symbols below are spelled the way the app spells them, which is the spelling the chord's own scale asks for rather than whichever accidental is easier to type.

  • Cdim7
  • Dbdim7
  • Ddim7
  • Ebdim7
  • Edim7
  • Fdim7
  • F#dim7
  • Gdim7
  • Abdim7
  • Adim7
  • Bbdim7
  • Bdim7

Voicings

Written in C, because that is the key the encyclopedia authors them in; every one transposes unchanged.

Root Position

C · Eb · Gb · A

intermediate

Octaves shown are the app's default ascending voicing.

Inversion 1 (same sound!)

Eb · Gb · A · C

intermediate

Octaves shown are the app's default ascending voicing.

Due to symmetry, all inversions are equivalent

Spread Voicing

C · Gb · A · Eb

advanced

Octaves shown are the app's default ascending voicing.

Stacked Thirds Spread (1-b5-b3-bb7)

C · Gb · Eb · A

advanced

Symmetric dim7 spread in minor 3rds across an octave

Inversion 2 (b5-bb7-1-b3)

Gb · A · C · Eb

intermediate

2nd inversion — every inversion of dim7 is another dim7

Rootless Upper Tensions (b3-b5-9-13)

Eb · Gb · D · A

expert

Rootless dim7 with the 9 added — diminished-scale color

Where it turns up

Passing chord, creates tension. Symmetrical - any inversion sounds the same. Use between chords a half-step apart.

Commonly swapped with

  • C7b9 (no root)
  • Any diminished a minor 3rd away

Progressions that use it

Every one of these is written out with the hands on a keyboard and on a stave.