Upgrading Your Chords From Triads To Sixth, Seventh, And Ninth Chords In The Key Of C

I’m excited to show you other chord qualities that are bigger and better than the triads that we learned in the previous lesson.

But before we go into all that, let’s do a quick review on the triads that we’ve learned.

A Review On Primary And Secondary Triads

In the last lesson, we covered primary and secondary triads in the key. Primary triads in the key of C major:

…are major triads of the first:

…fourth:

…and fifth degrees:

…while secondary triads are triads of the second:

…third:

…sixth:

…and seventh degrees:

The second, third, and sixth having a minor quality, and the seventh having a diminished quality.

In the key of C:

…the primary triads are the C major triad:

…F major triad:

…and G major triad:

…while the secondary triads of minor quality are the D minor triad:

…E minor triad:

…and A minor triad:

The secondary triad of the seventh degree is the B diminished triad:

…which is considered unstable because the interval between its first and fifth tones which are B and F:

…respectively, is a diminished fifth interval (aka – “tritone”.)

Now that we’ve reviewed primary and secondary triads, let’s go into learning sixth, seventh, and ninth chords.

Sixth Chords In The Key Of C

In classical music, the term sixth chord is used to refer to the first inversion of a triad. For example, playing the C major triad:

…in its first inversion:

…produces a sixth chord. It’s called the sixth chord because the interval between E and C:

…in this first inversion chord is a sixth interval.

A sixth chord is a triad with an added sixth tone – encompassing six degrees of the scale and there are two known qualities of sixth chords:

The major sixth chord
The minor sixth chord

The major sixth chord can be formed by adding a sixth tone to the major triad, while the minor sixth chord can be formed by adding a sixth tone to the minor triad.

Let’s quickly learn major and minor sixth chords in the key of C.

Major Sixth Chords

The major sixth chord is the scale degree sixth chord of the first and fourth degrees in the key of C:

To the regular C major triad:

…and F major triad:

…which are chords 1 and 4, a sixth tone can be added to form a major sixth chord.

So adding a sixth note (A):

…to the C major triad:

…produces the C major sixth chord:

In the same vein, adding a sixth (D):

…to the F major triad:

…produces the F major sixth chord:

So the C major sixth:

…and the F major sixth chords:

…are sixth chords of the first and fourth degrees in the key of C.

Minor Sixth Chords

The minor sixth chord can be formed by adding a sixth tone to the minor triad. The minor sixth chord can be formed on second degree of the scale.

So chord two in the key of C:

…which is the D minor triad:

…with a sixth tone (B):

…added to it, produces the D min6 chord:

…which is chord two:

…in the key of C:

The D minor sixth chord:

…is not always used as chord two because it is tritonic.

Attention: Tritonic chords are chords that contain the tritone.

Between F:

…being the third tone, and B:

…the sixth tone of the Dmin6th chord is a tritone.

It is the tritone that makes the Dmin6 chord:

…like every other minor sixth chord dissonant and unpleasant.

Seventh Chords In The Key Of C

The seventh chord is a chord that encompasses seven degrees of a given scale.

There are various classes of seventh chords ranging from the major seventh chord, to the minor seventh chord, to the dominant seventh chord, to the half-diminished seventh chord, to the diminished seventh chord, and other seventh chord classes.

In this lesson, we’ll be learning only five seventh chord qualities.

The Major Seventh Chord

The major seventh chord is formed by adding a note to a major triad, that is a major seventh interval above its root.

So, adding B:

…which is the major seventh interval above C:

…to the C major triad:

…produces the C major seventh chord:

The major seventh chord is the scale degree seventh chord of the first and fourth degrees in the key of C:

So, we would have the C major seventh chord:

…and the F major seventh chord:

…as chord one and chord four in the key of C.

The next seventh chord quality on my list is the minor seventh chord.

The Minor Seventh Chord

The minor seventh chord is formed by adding a note to a minor triad, that is a minor seventh interval above its root.

Minor seventh chords are formed on the second, third, and sixth degrees in the key of C. In the second degree in the key of C:

…where we have the D minor triad:

…adding a note to the D minor triad that is a minor seventh interval above D:

…which is C:

…produces a D minor seventh chord:

The same thing is obtainable in the third degree (E):

…where we can add D:

…which is a minor seventh above E:

…to the E minor triad:

…to form the E minor seventh chord:

In the sixth degree (A):

…adding a note to the A minor triad:

…that is a minor seventh interval above A:

…which is G:

…produces the A minor seventh chord:

So altogether, the D minor seventh chord:

…the E minor seventh chord:

…and the A minor seventh chord:

…are the scale degree seventh chords of the second, third, and sixth scale degrees in key of C major.

The Dominant Seventh Chord

Dominant seventh chords are chords of the fifth degree. The term dominant is the technical name that music scholars associate with the fifth degree of the scale.

Basically, the dominant seventh chord is simply the chord of the fifth degree:

…in the key of C. Adding a note to the G major triad:

…that is a minor seventh interval above G:

…which is F:

…produces the G dominant seventh chord.

So, adding an F:

…to G major triad:

…produces the G dominant seventh chord:

The Half-Diminished Seventh Chord

The half-diminished seventh chord is formed by adding a note to a diminished triad, that is minor seventh interval above its root.

For example, on the seventh degree, where we have the B diminished triad:

…adding a note that is a minor seventh interval above B:

…which is A:

…produces the B half-diminished seventh chord:

…which is chord seven in the key of C:

The Diminished Seventh Chord

Although there is no diminished seventh chord quality in the key of C major:

…but we’ll be borrowing it from the key of C minor (a parallel key.) In the key of C minor, using the C harmonic minor scale:

…we can form a diminished seventh chord from its seventh tone by stacking B:

…D:

…F:

…and Ab:

…together, to form the B diminished seventh chord:

The B diminished seventh chord:

…can be formed by adding a note that is a diminished seventh interval above B:

…which is Ab:

Ninth Chords In The Key Of C

Ninth chords are basically chords that encompass nine degrees of a given scale. They are known as extended chords because they exceed the compass of an octave and can be challenging to the average human hand.

In this segment, we’ll be covering three important ninth chord qualities:

Major ninth
Minor ninth
Dominant ninth

The Major Ninth Chord

The major ninth chord can be formed on the first:

…and fourth degrees:

…in the key of C major:

Feel free to consider the major ninth chord as a major seventh chord:

…with an additional ninth tone:

…known as an extension. It is the extension of the major seventh chord:

…with that ninth (D):

…that forms the major ninth chord:

There are two major ninth chords in the key of C:

The C major ninth chord:

…and the F major ninth chord:

The C major ninth chord is chord one:

…while the F major ninth is chord four:

The Minor Ninth Chord

The minor ninth chord is the scale degree chord of the second:

…and sixth degrees:

…in the key of C major:

The D minor seventh chord:

…can be extended by adding a ninth (E):

…to it and this produces the D minor ninth chord:

The A minor seventh chord:

…can be extended by adding a ninth (B):

…to it and this produces the A minor ninth chord:

The minor ninth chord can be formed on the second:

…and sixth degrees:

…in the key of C:

In addition to that, we can have a minor ninth chord on the third degree in the key of C (which is E):

…however, the E minor ninth chord:

…is a chromatic chord.

The ninth tone of the E minor ninth chord:

…(which is F#) is chromatic or foreign to the key of C major:

The Dominant Ninth Chord

The dominant ninth chord is an extended chord of the fifth degree of the scale that can be formed by adding the ninth (an extension) to the basic dominant seventh chord.

The G dom7 chord:

…which is the the seventh chord of the fifth degree (aka – “dominant seventh”), can be extended by the addition of an extension (the ninth) which is A:

…to form the G dominant ninth chord:

…which is the ninth chord of the fifth degree.

An Overview Of All The Chord Qualities Covered In The Key Of C

As we come to the end of this lesson, it is important for us to learn all the chord qualities covered in the course of this lesson in the key of C.

Sixth Chords

C major sixth:

C minor sixth:

Seventh Chords

C major seventh:

C minor seventh:

C dominant seventh:

C half-diminished seventh:

C diminished seventh:

Submission: The proper spelling of the C diminished seventh chord is C-Eb-Gb-Bbb, however we are spelling it as C-Eb-Gb-A because my chord share tool does not spell double-flat notes yet.

Ninth Chords

C major ninth:

C minor ninth:

C dominant ninth:

“Just Before We Round Up…”

Now that you’ve learned these chords, I want you to practice playing them (chords of the second and sixth degrees). Practice playing minor chords separately and practice major chords separately and dominant chords separately. And that’s how it works.

So if I want to organize my practice for the day, I could start by playing major triads of the first and fourth degrees, major seventh chords of the first and fourth degrees, and ultimately major ninth chords of the first and fourth degrees.

This will enable me to grow the chords from basic triads to sevenths, and to extended chords.

Also for chords of minor quality (minor chords), starting from minor triads in the second, third, and sixth degrees to minor seventh chord in the second, third, and sixth degrees, and then ultimately minor ninth chords which are extended chords of the second, third, and sixth degrees.

You can also take a look at dominant chords which starts from a major triad in G major triad:

…to G dominant seventh chord:

…to the G dominant ninth chord:

Great job! I’ll see you in the next lesson.