Diminished chords traditionally take the 7th position in a major key. Their spelling is generally 1-b3-b5, read as 1 flatted-3 flatted-5 for a half diminished chord, or 1-b3-b5-bb7 (double flatted 7 or a sixth note actually) for a full diminished chord or seventh diminished chord.
Diminished chords pull strongly toward the major chord which is a half-step higher. Interestingly, the intervals between the successive notes are all minor thirds, which makes their spelling symmetrical and quite easy to define and use in a number of situations. Because of this symmetry, each diminished chord can have 4 different letter names, since each note in the diminished chord spelling can be used to name the chord. [Read more…]