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Bb dim Piano Chord

    Piano Diagram of Bb dim in Root Position

    Bb dim Chord - Root Position - Piano Diagram

    The Bb dim chord is the diminished triad built upon the Bb key. It is built by combining the Root note (Bb), the minor 3rd (Db), and the diminished 5th (Fb) notes from the B-flat scale. Keep reading to learn more about the music theory behind this chord.


    Structure of Bb dim


    Bb, Db, Fb


    R, m3, d5


    Fingers Position

    Left Hand

    3, 2, 1

    4, 2, 1

    Right Hand

    1, 2, 4

    1, 3, 5


    Bb dim Chord Inversions


    The Bb dim chord has a total of 2 inversions:

    Root Position: Bb Db Fb
    1st Inversion: Db Fb Bb
    2nd Inversion: Fb Bb Db

     Piano Keyboard Diagrams

    Music Theory and Harmony of Bb diminished


    What are Diminished Chords?

    In music theory, diminished chords are classified as triads just like major, minor, and augmented chords. A diminished triad is a chord that has a root note, a minor 3rd, and a diminished 5th. They are often abbreviated with a small circle (°) or the letters “dim”. For example, an A diminished chord would be written as A° or Adim.

    The interval between the root and the diminished 5th is called a “tritone” and creates a dissonant sound that adds tension and instability. Diminished triads are commonly used as transitional chords, leading to more stable chords.

    Different types of Diminished Chords

    1. Diminished triads are usually considered unstable and are often used as transitional chords that create tension and lead to a more stable chord.
    2. There are also diminished seventh chords, which include an added diminished seventh interval above the root note. These chords are often written as °7 or dim7. They can also be used as a substitute for dominant 7th chords.
    3. Additionally, there are half-diminished chords (also known as minor seventh flat five chords), which include a minor seventh interval instead of a diminished seventh.

    But for now, let’s explore the simpler diminished triad in the key of Bb.


    Building the Bb dim Chord: Different Approaches

    Starting from a Major Scale

    To build a diminished chord, you begin by selecting the root note, the 3rd note, and the 5th note of the major scale. Next, you lower the 3rd and the 5th note by one half-step.


    Bb Major Diatonic Scale up to octave

    Bb Major Scale


    Bb Major Diatonic Scale up to octave Keyless Notation

    Bb Major Scale – Keyless Notation


    So, if you want to build a Bb diminished chord, you would start with the Bb major chord, which consists of the notes Bb, D, and F. Then, you would lower the third note, D, by one half-step to get Db and lower the fifth note, F, by one more half-step to get Fb (E). The resulting notes, Bb, Db, and Fb form the Bb diminished chord.


    by Combining 3rds

    Alternatively, a diminished chord can be built by stacking two minor 3rd intervals on top of each other. To get this chord, you begin with the root note and then raise it by a minor 3rd. Next, you raise the third note by another minor 3rd. The resulting chord will consist of three notes that are spaced an equal distance apart.

    m3 + m3 = diminished Chords

    To form a Bb dim chord, you start with the root note Bb and raise it by a minor 3rd to Db. Then, you raise the third note Db by another minor 3rd to Fb. This results in a Bb dim chord consisting of the notes Bb, Db, and Fb.


    How to Use Bb dim in a Chord Progression


    Harmonic functions describe how chords sound together in a specific key and context. In Western music, there are seven main harmonic functions, one for each note of the diatonic scale. Major chords are represented by capitalized Roman numerals, while minor chords are represented by lowercase ones.

    The tables below show the Ab minor scale and its relative major scale, both of which include a Bb diminished chord.

    The Bb diminished chord is found on the second scale degree (II) in the Ab minor scale and on the seventh scale degree (VII) in the Cb major scale. However, for a more comprehensive list of its uses, please refer to the dim7 tables, where I delve deeper into some of the features of these chords.


    on Natural minor Scale

    Minor Scale i ii III iv v VI VII
    Ab Ab min Bb dim Cb Maj Db min Eb min Fb Maj Gb Maj
    • Supertonic chord in A minor


    on Major Scale

    Major Scale I ii iii IV V vi vii
    Cb Cb Maj Db min Eb min Fb Maj Gb Maj Ab min Bb dim
    • Leading tone chord in Cb Major


    A-flat minor and C-flat major are uncommon keys, therefore, musicians often use their enharmonic equivalent keys, G#minor and B major, which have fewer accidentals, making them easier to read and play.


    Bb dim Chord Function in Major and Minor Keys

    Understanding Scale Degrees

    When we create chords from a scale, each note in the scale is given a specific degree that reflects its position in the scale. In the diatonic major scale, there are seven degrees, and each degree plays a unique role in the overall harmony of the scale.

    1. The first degree of the scale is called the Tonic, and it’s like the home base of the music. It provides a stable tonal center that serves as the foundation for the scale.
    2. The second degree of the scale is called the Supertonic. It’s often used as a transitional note between the tonic and other notes in the scale.
    3. The third degree of the scale is called the Mediant. It’s located halfway between the tonic and dominant notes and helps to establish whether the scale is major or minor.
    4. The fourth degree of the scale is called the Subdominant. It’s often used as a complementary harmony to the dominant.
    5. The fifth degree of the scale is called the Dominant. It generates tension and a sense of expectation, and it’s usually resolved by returning to the tonic.
    6. The sixth degree of the scale is called the Submediant. It’s often used as a transition between the dominant and tonic, and it provides a sense of stability and restfulness to the music.
    7. The seventh degree of the scale is called the Leading tone. It’s located one half step below the tonic and produces a strong sense of tension and a desire to resolve to the first degree.


    Bb dim in Ab Minor

     In the key of Ab minor, the Bb diminished chord serves as the supertonic chord, which is the chord built on the second degree of the scale. It is often used as a passing chord to create movement between other chords in a progression.

    i ii III iv v VI VII
    Ab min Bb dim Cb Maj Db min Eb min Fb Maj Gb Maj


    Bb dim Chord Progressions as ii degree

    Here are some examples of chord progressions that feature the Bb diminished as the supertonic chord.

    ii iv V i
    ii iv V i
    Bb dim Db min Eb Maj Ab min

    In minor keys, the fifth degree (v) is often replaced with a dominant 7th chord (V7) or a major chord (V) in the context of triads. This chord is derived from the harmonic minor scale and is commonly used in this position.


    iv ii i
    iv ii i
    Db min Bb dim Ab min


    VII ii i
    VII ii i
    Gb Maj Bb dim Ab min


    ii V i
    ii V i
    Bb dim Eb Maj Ab min


    Bb dim in Cb Major

    Check A# dim in B Major


    Alternative Names for Bb Diminished

    • Bb°
    • Bbdim
    • Bb diminished
    • B-flat diminished



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