• A Lesson On The Seventh Chord Types For The Diminished Triad

    in Chords & Progressions,Experienced players,Piano,Theory

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    I this lesson, you’ll learn about the seventh chord types for the diminished triad.

    Although the diminished triad is one of the four known triads, it is not always emphasized like the major and minor triads, consequently, most beginners are not familiar with the diminished triad.

    Major seventh and minor seventh chords sound harmonically advanced than major and minor triads respectively, and that’s why a vast majority of musicians who have grown past the beginner’s level graduate from triads to seventh chords.

    Before we explore the seventh chord types for the diminished triad, let’s discuss briefly on the diminished triad.

    “What Is A Diminished Triad?”

    The diminished triad is the chord of the seventh degree in the major key. For example, in the key of C major:

    …where the seventh tone is B:

    …the chord of the seventh tone which consists of B, D, and F:

    …is the diminished triad.

    The term diminished is derived from the interval between the first and fifth tones (B and F):

    …which is a diminished fifth interval.

    “Check Out All The Diminished Triads On The Keyboard…”

    C diminished triad:

    C# diminished triad:

    D diminished triad:


    D# diminished triad:

    E diminished triad:

    F diminished triad:

    F# diminished triad:

    G diminished triad:

    G# diminished triad:

    A diminished triad:

    A# diminished triad:

    B diminished triad:

    Seventh Chord Types For The Diminished Triad

    The Diminished Major-Seventh Chord

    One of the seventh chord types for the diminished triad is the diminished major seventh chord.

    A classic example of the diminished major seventh chord is the D diminished major seventh chord:

    …which consists of the D diminished triad:

    …and C#:

    …which is a seventh chord tone that is a major seventh above the root of the diminished triad (D):

    If diminished triads are part of your active chordal vocabulary and you’ll love to play its seventh chord type, feel free to make the diminished major seventh chord an option.

    “Quick Formation Of The Diminished Major Seventh Chord…”

    The seventh tone that can be added to the diminished triad to form the diminished major seventh chord is a major seventh above the root of the diminished triad.

    In the case of the D diminished major seventh chord:

    …we added C#:

    …which is a major seventh above D:

    …to the D diminished triad:

    …to form the D diminished major seventh chord.

    So, in the formation of the diminished major seventh chord, the seventh tone of the major scale in the key you’re in, is added to the diminished triad.

    Given the G diminished triad:

    …the G diminished major seventh chord can be formed by adding the seventh tone of the major scale in the key of G major:

    …which is F#:

    …to the G diminished triad:

    This produces the G diminished major seventh chord:

    The Half-Diminished Seventh Chord

    Another seventh chord option for the diminished triad is the half-diminished seventh chord.

    A classic example of the half-diminished seventh chord is the D half-diminished seventh chord:

    …which consists of the D diminished triad:

    …and C:

    …which is a seventh chord tone that is a minor seventh (aka – “flat seven”) above the root of the diminished triad (D):

    “Quick Formation Of The Half-Diminished Seventh Chord…”

    The seventh tone that can be added to the diminished triad to form the half-diminished seventh chord is a minor seventh above the root of the diminished triad.

    In the case of the D half-diminished seventh chord:

    …we added C:

    …which is a major seventh above D:

    …to the D diminished triad:

    …to form the D half-diminished seventh chord:

    So, in the formation of the half-diminished seventh chord, the “flat seventh” tone of the major scale in the key you’re in, is added to the diminished triad.

    Given the G diminished triad:

    …the G half-diminished seventh chord can be formed by adding the “flat seventh” tone of the major scale in the key of G major:

    …which is F:

    …to the G diminished triad:

    This produces the G half-diminished seventh chord:

    The Diminished Seventh Chord

    The final seventh chord option for the diminished triad on our list for today is the diminished seventh chord.

    An example of the diminished seventh chord is the D diminished seventh chord:

    …which consists of the D diminished triad:

    …and Cb:

    …which is a seventh chord tone that is a diminished seventh (aka – “double-flat seven”) above the root of the diminished triad (D):

    “Quick Formation Of The Half-Diminished Seventh Chord…”

    The seventh tone that can be added to the diminished triad to form the diminished seventh chord is a diminished seventh above the root of the diminished triad.

    In the case of the D diminished seventh chord:

    …we added Cb:

    …which is a diminished seventh above D:

    …to the D diminished triad:

    …to form the D diminished seventh chord:

    So, in the formation of the diminished seventh chord, the “double-flat seventh” tone of the major scale in the key you’re in, is added to the diminished triad.

    Attention: The double-flat seventh tone of the major scale is derived by lowering the seventh tone of the major scale twice.

    Given the G diminished triad:

    …the G diminished seventh chord can be formed by adding the “double-flat seventh” tone of the major scale in the key of G major:

    …which is Fb:

    …to the G diminished triad:

    This produces the G half-diminished seventh chord:

    “Wait A Minute! Here’s How We Derived The Double-Flat Seventh Tone…”

    The seventh tone in the key of G major:

    …is F#:

    Lowering the seventh tone (which is F#) twice, produces the double-flat seventh note. Lowering F#:

    …by the first half-step (takes us to F):

    …then by the second half-step (to Fb):

    So, the double-flat seventh tone in the key of G is Fb.

    Final Words

    Instead of the diminished triad, there are three seventh chord types that can be used and we’ve covered them in this lesson.

    We’ll not stop at that! In a subsequent lesson, we’ll explore the resolution and application of these diminished seventh chord types.

    See you then!

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    Onyemachi "Onye" Chuku is a Nigerian musicologist, pianist, and author. Inspired by his role model (Jermaine Griggs) who has become his mentor, what he started off as teaching musicians in his Aba-Nigeria neighborhood in April 2005 eventually morphed into an international career that has helped hundreds of thousands of musicians all around the world. Onye lives in Dubai and is currently the Head of Education at HearandPlay Music Group and the music consultant of the Gospel Music Training Center, all in California, USA.




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