Bass · diminished seventh
Bdim7 Chord on Bass
B Diminished 7th is B, D, F, Ab — the 1-b3-b5-bb7 pattern of a diminished seventh chord. Here is the shape, the audio, and what usually goes wrong.
There is no open Bdim7 on bass. The one shape below sits up the neck and is rated advanced.
Start here — Root-b3-b5-bb7 Shape (6th fret)
Sits at fret 6 — tighter and brighter than the low shapes, and high enough to keep out of the way of anyone playing the open version underneath.
What beginners get wrong
Moving in and out of it
The shape above: Root-b3-b5-bb7 Shape (6th fret).
Listening: each shape above has its own play button, and each one plays the notes that shape actually produces — not a generic triad.
Bdim7 on other instruments
Same notes, different hands. Every link below is a real page with diagrams and audio.
Chords next door
Same root, different colour — and all of them playable on bass.
Bdim7 on Bass — questions people ask
What is the easiest way to play Bdim7 on bass?
“Root-b3-b5-bb7 Shape (6th fret)” — which we rate advanced — is the easiest Bdim7 shape on bass. Sits at fret 6 — tighter and brighter than the low shapes, and high enough to keep out of the way of anyone playing the open version underneath. There is no open Bdim7 on bass, so a barre is unavoidable; this is the least demanding one.
What notes are in the B Diminished 7th chord?
B Diminished 7th is B, D, F, Ab — the 1-b3-b5-bb7 interval pattern of a diminished seventh chord. Every voicing on this page uses those notes and nothing else; they just appear in a different order and octave.
What can I play instead of Bdim7?
The nearest stand-ins on bass that keep the same root are Bsus4, Bsus2, B. They keep the root and the fifth and only change what sits in the middle, so most songs still work — but check the swap against the melody, because the note you removed may be the one the tune is singing.
Can I play Bdim7 on other instruments?
Yes. Bdim7 is the same set of notes everywhere; only the fingering changes. This site has diagrams and audio for it on guitar, piano, ukulele, mandolin, banjo.
Learn the theory behind Bdim7
The shape gets your fingers there. These explain why it sounds the way it does.
Functional Harmony: Three Roles, One Engine
Diminished chords are almost always doing a job. This explains which one.
6 min read
Cadences — The Four Ways a Phrase Ends
Where all that tension goes — how the chord resolves into the next one.
4 min read
Voice Leading — Hold What You Can, Move Only What You Must
Half-steps do the work here. Voice leading is how you find them.
6 min read