We are going to briefly discuss the diminished chord on the bass guitar.
The diminished chord has the symbol Co
In this diminished chord you will simply lower the fifth and third by half. It is unlike the Augumented chord where we raise the fifth by half.
i.e we have 1 3 5
C E G
the augumented chord becomes 1 b3 b5
C Eb Gb
Remember that in the chord shape diagram above the white circles stand as the root of the chord.