• Extending The Dominant Seventh Chord (Part 1)

    in Chords & Progressions,Piano,Theory

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    In today’s lesson, we’ll be extending the dominant seventh chord.

    The dominant seventh chord is one of the harshest chords to be discovered in music. It is traditionally said to be discordant and has the tendency to resolve to a more stable chord when played/heard.

    Over time, things have changed. It turned out to be that the degree of dissonance that the dominant seventh chord is associated with, is no longer dissonant enough to modern day listeners.

    Further reading: Yesterday’s Dissonance, Today’s Consonance.

    This lesson would show you exactly what to do to expand the dominant seventh chord, making it more appealing to modern day listeners.

    Review On The Dominant Seventh Chord

    According to Jermaine Griggs, “The dominant seventh chord is a chord of the fifth degree (with four notes), that encompasses seven degrees of the scale.”

    The Definition Of The Dominant Seventh Chord

    You’ll have a clearer perception of the term dominant seventh chord if we break it down word for word.

    A chord is a collection of related notes.

    The term dominant is the technical name that music scholars call the fifth tone of the scale.

    A seventh is an interval that encompasses seven degrees of a scale.

    If you put these three terms together, you’ll have an absolute understanding of what the dominant seventh chord is.

    The Formation Of The Dominant Seventh Chord

    The dominant seventh chord can be formed using the mixolydian mode. Let’s do a little review on the mixolydian mode for the sake of those who don’t know what the mixolydian mode is.

    To form the mixolydian mode, lower the seventh degree of the major scale by a half step. For example,inĀ  the C major scale:

    …where the seventh tone of the scale is B:

    …lowering B (by a half step) to Bb:

    …produces the C mixolydian mode:

    Using the pick-skip technique, you can form the C dominant seventh chord thus…

    Pick C:

    …skip D and pick E:

    …skip F and pick G:

    …skip A and pick Bb:

    Put together, we have a chord that encompasses seven scale degrees.

    The Resolution Of The Dominant Seventh Chord

    The dominant seventh chord resolves a fifth below its root (or a fourth above its root.)

    The C dominant seventh chord:

    …we formed resolves a perfect fifth below its root to an F major:

    …or F minor:

    …triad.

    Beyond this point, it is assumed that you are familiar with the dominant seventh chord, therefore, our focus now is on expanding it.

    “Why Should I Expand The Dominant Seventh Chord?”

    Beyond the harmonic realm of seventh chords, lies what music scholars call extended chords.

    Therefore I want you to acknowledge that the term expanding here means that we’re literally making the chord larger in size and thicker in texture, among other things.

    “…Larger In Size”

    Going by the traditional principle of chord formation in thirds (aka -“tertian harmony“), we are basically forming chords by stacking notes in thirds.

    Expanding the dominant seventh chord increases its size or width and compass. Instead of encompassing seven degrees of the mixolydian scale, we’ll have bigger chord structures that encompass nine, eleven, and thirteen degrees of the mixolydian scale respectively.

    Due to the fact that chords are built in thirds, the number for chord tones are always odd numbers – first, third, fifth, seventh, ninth, eleventh, and thirteenth.

    “…Thicker In Texture”

    Texture refers to the layers of notes that are heard at once. The regular dominant seventh chord has a 4-note texture.

    Expanding the dominant seventh chord thickens its texture from a four note chord (aka – “tetrad”):

    …to a five note chord:

    …six note chord:

    …or a seven note chord:

    Consequently, the dominant seventh chord graduates from being lighter in texture, to a full-sounding chord, virtually involving all the tones of the scale. This expanded dominant chord:

    …has all the tones of the C mixolydian mode

    …arranged in thirds.

    Now, that I’ve explained the rationale behind the expansion of the dominant seventh chord to you, let’s proceed to the extension of the dominant seventh chord.

    Extending The Dominant Seventh Chord

    From what we covered in an earlier segment, the dominant seventh chord is traditionally built on harmony in thirds (aka – “tertian harmony“), therefore, extending it would also be in thirds.

    Basically, the choice of third is determined by the mixolydian scale, which is the underlying scale of chords in the dominant family.

    The Dominant Ninth Chord

    The dominant ninth chord is an extended dominant chord that encompasses nine degrees of the mixolydian mode. Here’s how to form the dominant ninth chord from the regular dominant seventh chord.

    Using the C mixolydian scale:

    …we can add a third to the C dominant seventh chord:

    A third above C-E-G-Bb:

    …is D:

    Altogether, C-E-G-Bb-D:

    …is a dominant chord quality that encompasses nine degrees of the mixolydian scale, which is known to music scholars as the C dominant ninth chord.

    The Dominant Eleventh Chord

    Here’s another extended chord in the dominant family. Here’s how to form the dominant eleventh chord from the dominant seventh chord.

    Using the C mixolydian scale:

    …we can add a third to the C dominant seventh chord:

    A third above C-E-G-Bb:

    …is D:

    …and another third above C-E-G-Bb-D:

    …is F:

    Altogether, C-E-G-Bb-D-F:

    …encompasses eleven degrees of the mixolydian scale, and is known to music scholars as the C dominant eleventh chord.

    Attention: The dominant eleventh chord is rarely used in music for a variety of reasons. Click here to learn more about this.

    The Dominant Thirteenth Chord

    Thirteenth chords are the largest extended chord types. The dominant thirteenth chord can formed using the same procedure we used for the dominant ninth and eleventh chords respectively. Check it out…

    Using the C mixolydian scale:

    …we can keep adding thirds to the C dominant seventh chord:

    …until we encompass thirteen degrees of the C mixolydian mode:

    A third above C-E-G-Bb:

    …is D:

    Another third above C-E-G-Bb-D:

    …is F:

    …and another third above C-E-G-Bb-D-F:

    …is A:

    Altogether, C-E-G-Bb-D-F-A:

    …encompasses thirteen degrees of the mixolydian scale, and is known to music scholars as the C dominant thirteenth chord.

    Attention: The dominant thirteenth chord is usually played either with an omitted or raised eleventh.

    Dominant Seventh Chord Extensions

    While extending the dominant seventh chord, we added other notes to it in thirds. These notes are known as extensions, because they extend the basic dominant seventh chord.

    There are three diatonic extensions – the ninth, eleventh, and thirteenth and they are related to the second, fourth, and sixth tones of the natural major scale respectively. Check out this example using the C dominant seventh chord.

    The extensions of the C dominant seventh chord:

    …are D:

    …the second tone of the C major scale, F:

    …the fourth tone of the C major scale, and A:

    …the sixth tone of the C major scale.

    Irrespective of the key, always remember that the second, fourth, and sixth tones of the natural major scale are the ninth, eleventh, and thirteenth extensions.

    Final Thoughts

    Now that you know how to extend the dominant seventh chord, remember that they are not substitutes to the basic dominant seventh chord.

    There are still a thousand and one harmonic situations where the basic dominant seventh chord can fit into that extended dominant seventh chords can’t and that’s the subject of our discussion in another post.

    Thank you for your time.

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    Hello, I'm Chuku Onyemachi (aka - "Dr. Pokey") - a musicologist, pianist, author, clinician and Nigerian. Inspired by my role model Jermaine Griggs, I started teaching musicians in my neighborhood in April 2005. Today, I'm privileged to work as the head of education, music consultant, and chief content creator with HearandPlay Music Group sharing my wealth of knowledge with hundreds of thousands of musicians across the world.

    Attention: To learn more about this, I recommend our 500+ page course: The "Official Guide To Piano Playing." Click here for more information.




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    { 4 comments… read them below or add one }

    1 zino

    good

    Reply

    2 Marie

    Very interesting but how in the world does a person play such humongous chords? You need three hands, two for these chords and one for the melody.

    Reply

    3 kenny

    interesting and educating, I’ll love to see the application of the dominant seventh chord.

    Reply

    4 Nene

    I think you should do another part explaining different ways we can resolve the chord and some scales to play over it.

    Reply

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