• Revealed: The Formation Of Major Seventh Chords Using The Diminished Octave Interval

    in Chords & Progressions,Piano,Theory

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    Invest the next 20 minutes in this lesson, and gain another perspective to the formation of major seventh chords.

    Warning: What you’re about to learn will give you a new perspective to major seventh chords.

    We’ll be learning four different major seventh chords in this lesson and how their formation can be approached, using the smartest way possible.

    Before we get started, permit me to do a review on the major seventh chord.

    A Breakdown On The Major Seventh Chord

    According to Jermaine Griggs, “…a chord is a collection of three or more related notes [agreeable or not], played[or heard] together.” Hence, the major seventh chord is a collection of related notes.

    “Let’s Take A Look At Some Of The Key Words In The Definition Of Chords…”

    There are two keywords that can boost your perception of the major seventh chord and they are…

    #1 – “…three or more…”

    It takes at least three notes to form a chord. Although there’s a harmonic relationship when two notes are played together, a collection of two notes is rather considered as an interval – which is the building block of chords.

    Attention: The major seventh chord is usually a collection of four notes.

    #2 – “…related notes…”

    Although a chord can be defined as a collection of three or more notes, it’s not every collection of three or more notes that can be considered as a chord. What leads to the consideration of three or more notes as a chord is the relationship between the notes.

    The notes of a chord can be related in two ways – by a scale and a class of harmony.

    The relationship between the notes of the C major scale:

    …and third intervals produces the C major seventh chord:

    The following intervals…

    C-E:

    E-G:

    G-B:

    …are all third intervals, while C, E, G and B:

    …are the first, third, fifth and seventh tones of the C major scale:

    #3 – “…agreeable or not…”

    The harmonic relationship between notes produces one of these outcomes…

    • Concord
    • Discord

    Concord is a pleasant combination while discord is an unpleasant combination of notes.

    Definition Of The Major Seventh Chord

    The major seventh chord is a tertian chord that consists of the first, third, fifth and seventh tones of the major scale – encompassing an interval of a seventh.

    The major seventh chord is a tertian chord formed by the relationship between the tones of the major scale. In a previous lesson, we learned that tertian chords are a product of tertian harmony – a class of harmony that structures chords in third intervals.

    With third intervals in mind, anyone can form the major seventh chord using any given major scale on the keyboard. Using the C major scale:

    …the major seventh chord can be formed thus…

    A third from C:

    …is E:

    A third from C-E:

    …is G:

    A third from C-E-G:

    …is B:

    Altogether, that’s the C major seventh chord.

    “Alternatively…”

    The major seventh chord can be formed by outlining the first, third, fifth and seventh tones of any given major scale. In the D major scale:

    …outlining the first, third, fifth and seventh tones which are D, F#, A and C#:

    …produces the D major seventh chord.

    Warning: Although there’s a long-established/conventional major seventh chord (which we just did a review on), there are other major seventh chords that every serious musician must know. Do NOT read beyond this segment if you’re not ready to learn what these major seventh chords are.

    Another Perspective To Major Seventh Chords

    Although there’s a major seventh chord well known, there are also other major seventh chords and I’ll be exposing them to you in this segment.

    I want to start by defining major seventh chords as chords that have the major seventh interval as an intervallic constituent.

    The major seventh interval is the interval formed by the relationship between the first and seventh tone of the major scale. In the key of C:

    …the relationship between C and B:

    …(which are the first and seventh tones) produces a major seventh interval.

    “Did You Know…”

    The major seventh chord is just one out of the several chords that have the major seventh interval as an intervallic constituent. Here are some of them:

    • The minor-major seventh chord
    • The diminished-major seventh chord
    • The augmented-major seventh chord

    “Here’s Another Perspective To Major Seventh Chords…”

    Kindly permit me to use C as a reference.

    The C major triad:

    …and a C major seventh interval:

    …produces the C major seventh chord:

    The C minor triad:

    …and a C major seventh interval:

    …produces the C minor-major seventh chord:

    The C diminished triad:

    …and a C major seventh interval:

    …produces the C diminished-major seventh chord:

    The C augmented triad:

    …and a C major seventh interval:

    …produces the C augmented-major seventh chord:

    The Major Seventh And Diminished Eighth Intervals

    Major seventh chords can be considered as chords that have the major seventh interval as an intervallic constituent.

    The relationship between the four known triad qualities (major, minor, diminished and augmented) and the major seventh interval, produces various major seventh chord qualities:

    We’re taking this study to another level by introducing the diminished eighth interval (aka – ‘diminished octave”) – which is an enharmonic equivalent of the major seventh interval.

    Attention: Enharmonic intervals are intervals that sound alike, but differ in structure and function.

    The diminished octave interval is formed by lowering the octave by a half step. In the perfect octave (C-C):

    …lowering this C:

    …by a half step to Cb:

    …produces C-Cb:

    …a diminished octave interval.

    A contrast between the C diminished octave interval:

    …and the C major seventh interval:

    …shows different spelling. However, when played both of them sound alike.

    Consequently, we’ll be using the diminished octave and major seventh interval interchangeably in the formation of major seventh chords.

    Although this makes the chord formation process easier, it is important to note that, when spelling the chord formed, one should change the diminished octave interval to a major seventh interval to avoid errors in spelling.

    The Major Seventh Interval Vs The Diminished Eighth Interval

    The formation of major seventh chords is easier to accomplish with the diminished octave.

    The formation of the major seventh interval requires a knowledge of the major scale. In other words, you need to know the first and seventh tones of the scale before you form the major seventh interval.

    Conversely, the diminished octave is easier to form because all you need to do to form a diminished octave interval is to lower the upper note of the octave by a half step. Believe it or not, the octave is one of the simplest interval to form.

    Instead of thinking about the first and seventh tones of the D major scale, it’s easier to quickly play the D octave:

    …and diminish its upper note (D):

    …by a half step (to Db):

    …to form D-Db:

    …a D diminished octave, which doesn’t necessarily have the same spelling with the regular D major seventh interval – D-C#:

    …but sounds alike.

    “In A Nutshell…”

    I’m simplifying the process for you by showing you how you can use the diminished octave (an enharmonic equivalent of the major seventh interval) in the formation of major seventh chords.

    Let’s go right into the formation of major seventh chords using the diminished octave.

    The Formation Of Major Seventh Chords Using The Diminished Octave

    Quickly, here’s how major seventh chords can be formed using the diminished octave. We’ll be using C as our reference. Once the process is understood, kindly transpose to all twelve keys.

    The Major Seventh Chord Starting From C

    Playing the C major triad in octave position:

    …and diminishing the octave:

    …produces the C major seventh chord:

    The Minor-Major Seventh Chord Starting From C

    Playing the C minor triad in octave position:

    …and diminishing the octave:

    …produces the C minor-major seventh chord:

    The Diminished-Major Seventh Chord Starting From C

    Playing the C diminished triad in octave position:

    …and diminishing the octave:

    …produces the C diminished-major seventh chord:

    The Augmented-Major Seventh Chord Starting From C

    Playing the C augmented triad in octave position:

    …and diminishing the octave:

    …produces the C augmented major seventh chord:

    Final Words

    I’m excited to share my perspective with you on major seventh chords and also on a smart way to form them on the piano. Although the use of the diminished octave distorts the actual spelling of the chords, it simplifies the formation process and that’s our goal in this lesson.

    We’ll continue our discussion in another lesson by learning about little known ways major seventh chords can be used in 2-5-1 chord progressions.

    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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