Diminished 7th chords for guitar
The dim7 (diminished seventh) is made up of a diminished triad (i.e. a minor triad with a lowered fifth) and a diminished seventh interval. The diminished seventh interval is a minor seventh that has been lowered a half note (identical to a straightforward sixth). In other words, the diminished seventh is constructed by putting four minor thirds on top of each other. Ex. Cdim7 consists of the notes C, Eb, Gb and Bbb (In this example, the diminished seventh interval is written as "Bbb", not as "A").
Scale fit: 8-tone scale