The formula for a diminished chord (often abbreviated to "dim" or written with a small B or minus sign) is: I b III bV bVII*
Thus the GB chord is constructed as such:
and the BbB chord is constructed:
You will notice that the notes contained in these two chords are identical. If you construct a DB or an EB they will also contain the same notes (arranged in a different order). Thus all four diminished chords will use the following arpeggio pattern:
This pattern can start on either the 4th, 3rd or 2nd strings. Each note of the pattern can be regarded as a root note of the four respective diminished chords.
Play the following diminished chord examples.