Construction
| Note | Interval | Degree |
|---|---|---|
| B♭ | Root | 1 |
| D♭ | Minor 3rd | ♭3 |
| F♭ | Diminished 5th | ♭5 |
Fingering
| Note | Key color | Right hand | Left hand |
|---|---|---|---|
| B♭ | black | thumb (1) | little finger (5) |
| D♭ | black | middle finger (3) | middle finger (3) |
| F♭ | white | little finger (5) | thumb (1) |
Right hand: thumb (1) on B♭, middle finger (3) on D♭, little finger (5) on F♭.
Left hand: little finger (5) on B♭, middle finger (3) on D♭, thumb (1) on F♭.
B♭ Diminished Inversions
- Root positionB♭ – D♭ – F♭
- 1st inversion (B♭dim/D♭)D♭ – F♭ – B♭
- 2nd inversion (B♭dim/F♭)F♭ – B♭ – D♭
Key Signature
A Diminished chord is built from symmetrical or ambiguous intervals, so it doesn't belong to a single key and has no key signature of its own.
Chords in the Key of B♭ Major
These are the triads built on each degree of B♭ Major:
How B♭ Diminished functions in a key
The same chord takes on a different harmonic role depending on the key it appears in. Here is where B♭ Diminished sits diatonically across the common keys:
- In C♭ major, B♭ Diminished is the vii° chord — the dominant.
- In A♭ minor, B♭ Diminished is the ii° chord — a predominant.
Scales That Include the B♭ Diminished
- B Major (vii°)
- G# Minor (ii°)
- C# Dorian (vi°)
- D# Phrygian (v°)
- E Lydian (#iv°)
- F# Mixolydian (iii°)
- G# Aeolian (ii°)
- A# Locrian (i°)
B♭ Diminished : Frequently Asked Questions
What notes are in B♭dim?
How do you play B♭dim on piano?
What are the inversions of B♭dim?
What keys contain B♭dim?
What is the difference between B♭dim and B♭m7♭5?
What is an easy B♭dim for small hands?
What are the frequencies of B♭dim?
What is the set class of B♭dim?
How do I transpose B♭dim to another key?
Is A♯dim the same as B♭dim?
B♭ Diminished in detail
Exact
Every pitch class is present and nothing outside the chord is added.
| Type | Notes | Semitones | Span | Omissions and additions | Set relation | Fit |
|---|---|---|---|---|---|---|
| Close, root position | B♭3 D♭4 F♭4 | 6 | 83 mm | none | identical | |
| Close, first inversion | D♭4 F♭4 B♭4 | 9 | 124 mm | none | identical | |
| Close, second inversion | F♭4 B♭4 D♭5 | 9 | 124 mm | none | identical | |
| Open, fifth on top | B♭2 F♭3 D♭4 | 15 | 206 mm | none | identical |
Reduced
A subset of the pitch classes: the identity is incomplete rather than altered.
| Type | Notes | Semitones | Span | Omissions and additions | Set relation | Fit |
|---|---|---|---|---|---|---|
| Root and third only | B♭3 D♭4 | 3 | 41 mm | omits F♭ | subset |
Spans are measured centre to centre at a 165 mm octave (standard keyboard geometry).
| Position | Bass note | Notes in order | Figured bass | Semitones | Span |
|---|---|---|---|---|---|
| Root position | B♭ | B♭3, D♭4, F♭4 | 5/3 | 6 | 83 mm |
| First inversion: B♭dim/D♭ | D♭ | D♭4, F♭4, B♭4 | 6/3 | 9 | 124 mm |
| Second inversion: B♭dim/F♭ | F♭ | F♭4, B♭4, D♭5 | 6/4 | 9 | 124 mm |
One position per chord tone in the bass. Spans are for close position: voiced inversions appear under Voicings.
| Progression | Key | Role | Sequence | Voice leading |
|---|---|---|---|---|
| ii°, v, i | G♯ minor | ii° | A♯dim to D♯m to G♯m | B♭dim opens the phrase |
| vii°, I | B major | vii° | A♯dim to B | B♭dim opens the phrase |
Root motion, common tones and voice displacement are computed from pitch class sets. Roman numerals follow common practice functional harmony.
Which keys it belongs to
| Key | Roman numeral | Function |
|---|---|---|
| G♯ minor | ii° | Predominant |
| B major | vii° | Dominant function |
Classification system: common-practice functional harmony.
Change one note
Chords a single note away, and what moving that note does.
| Chord | Change | Formula | Common tones |
|---|---|---|---|
| B♭m7♭5 | adds A♭ | 1 ♭3 ♭5 ♭7 | 3 |
| B♭dim7 | adds A♭♭ | 1 ♭3 ♭5 ♭♭7 | 3 |
| B♭m | F♭ becomes F | 1 ♭3 5 | 2 |
| B♭m7 | F♭ becomes F, A♭ | 1 ♭3 5 ♭7 | 2 |
| B♭mMaj7 | F♭ becomes F, A | 1 ♭3 5 7 | 2 |
| B♭m6 | F♭ becomes F, G | 1 ♭3 5 6 | 2 |
| B♭ | D♭, F♭ becomes D, F | 1 3 5 | 1 |
| B♭aug | D♭, F♭ becomes D, F♯ | 1 3 ♯5 | 1 |
| B♭sus2 | D♭, F♭ becomes C, F | 1 2 5 | 1 |
| B♭sus4 | D♭, F♭ becomes E♭, F | 1 4 5 | 1 |
Frequencies
| Note | MIDI | Frequency |
|---|---|---|
| B♭3 | 58 | 233.08 Hz |
| D♭4 | 61 | 277.18 Hz |
| F♭4 | 64 | 329.63 Hz |
Reference pitch A440, 12-TET, close root position.
Set theory: prime form, Forte number, interval vector
- Absolute pitch class set
- {10, 1, 4}
- Normal order
- [10, 1, 4]
- Prime form
- (036)
- Forte number
- 3-10
- Interval vector
- <002001>
| Pair | Interval | Semitones | Interval class |
|---|---|---|---|
| B♭ to D♭ | Minor third | 3 | 3 |
| B♭ to F♭ | Tritone | 6 | 6 |
| D♭ to F♭ | Minor third | 3 | 3 |
Where these facts come from
Every value on this page is derived from the note formula for a diminished applied to the root B♭, using standard music theory. Nothing here is hand-entered per chord, so the notes, intervals, inversions and frequencies cannot drift out of agreement with each other. Pitches assume 12-TET at A440.