• Eight Intervals That Are Essential To The Formation Of Triads And Seventh Chords

Our focus in this lesson is on intervals that are essential to the formation of triads and seventh chords.

Although there are many intervals in music theory and they can be overwhelming to learn and master, there are only eight intervals that are directly involved with the formation of chords and I’ll be showing you these intervals in this lesson.

Attention: Once these intervals are mastered in all twelve keys, there’s NO triad or seventh chord that you cannot form. Yes! That’s how essential these intervals are.

Let’s get started right away.

Eight Intervals That Are Essential To Triads And Seventh Chords

Now that we’re done reviewing triads and seventh chords, let’s go ahead and explore eight intervals that are essential to their formation.

Interval #1 – “The Minor Third Interval”

The minor third interval is the basic intervallic constituent for all minor, and diminished chords. Although they can be found in other chord types, but the distance between the first and third tones of all minor and diminished chords is a minor third interval.

Three half-steps from any given note is a minor third interval and a classic example is from C to Eb:

C to Db (first half-step):

Db to D (second half-step):

D to Eb (third half-step):

Attention: Although C to D# encompasses three half-steps, the interval between C and D# is NOT a minor third interval; it’s rather an augmented second interval. All minor third intervals must encompass three alphabet letters. For example, C to Eb encompasses three alphabet letters (C, D, and E.)

Take a look at the C minor eleventh chord:

…and tell me how many minor third intervals you can see.

There are three minor third intervals in the C minor eleventh chord:

C and Eb (is the first one):

G and Bb (is the second minor third interval):

D and F (is the third minor third interval):

Interval #2 – “The Major Third Interval”

The distance between the first and third tones of the major scale is known as the major third interval. Using the C major scale (as a reference):

…the major third interval is the distance between C and E:

…which are the first and third tones of the C major scale.

Although the major third interval can be found in other chords (like minor and half-diminished) but major, augmented, and dominant chords all have the major third interval as the distance between their first and third tone.

There are two major third intervals in the C minor eleventh chord:

Eb and G:

Bb and D:

How many major third intervals can you see in the C dominant thirteenth [sharp eleventh] chord:

Interval #3 – “The Perfect Fifth Interval”

The perfect fifth interval is the interval between the first and fifth tones of the major scale and that’s C and G:

…if we’re using the C major scale (as a reference):

The perfect fifth interval is the essential intervallic ingredient for a wide variety of chords: major, minor, and dominant. A lot of triads, sixth chords, seventh chords, added tone chords, and extended chords have the perfect fifth interval.

This is because the perfect fifth interval adds a lot of stability, completeness, and consonance to a chord. Other chords (like the diminished and augmented chords) that don’t have the perfect fifth interval sound scary, dissonant and have the tendency to resolve when played.

The C minor eleventh chord:

…has four perfect fifth intervals:

C and G:

Eb and Bb:

G and D:

Bb and F:

How many perfect fifth intervals can you find in the C major ninth chord:

Interval #4 – “The Diminished Fifth Interval”

Lowering the perfect fifth interval by a half-step produces the diminished fifth interval (aka – “inverted tritone”.)

If you’re already familiar with C and G:

…which is the perfect fifth interval, you can form the diminished fifth interval by lowering G:

…by a half-step (to Gb):

…to form C-Gb:

…which is a diminished fifth interval.

The diminished fifth interval is specifically found in diminished chords and some dominant chords as well and they are known for the characteristic dissonance they add to chords.

The B diminished seventh chord:

…has two diminished fifth intervals:

B and F:

D and Ab:

How many diminished fifth intervals can you find in the C dominant seventh [flat ninth] chord:

Interval #5 – “The Augmented Fifth Interval”

The augmented fifth interval is the main intervallic constituent of augmented chords; although it can be found in certain major and dominant chords as well.

Raising the perfect fifth interval by a half-step produces the augmented fifth interval.

The C perfect fifth interval (C-G):

…can be raised by a half-step and that entails raising G:

…by a half-step (to G#):

…to produce C-G#:

…which is an augmented fifth interval.

Classic examples of chords that have the augmented fifth interval are as follows:

The C augmented major seventh chord:

The C augmented seventh chord:

Interval #6 – “The Major Seventh Interval”

The major seventh chord encompasses the distance between the first an d the seventh tone of the major scale. In the key of C major:

…the first and seventh tones of the scale (which are C and B):

C:

B:

…can be played together (or separately) to form the C major seventh interval (C-B):

The major seventh interval can be applied in the formation of the following chords:

C major seventh chord:

C minor [major seventh] chord:

C augmented [major seventh] chord:

C diminished [major seventh] chord:

…and they are all basically the four main triad types (major, minor, augmented, and diminished) with the major seventh interval.

Interval #7 – “The Minor Seventh Interval”

Lowering the major seventh interval by a half-step produces the minor seventh interval.

Using the “C-B” major seventh example:

…you can form the minor seventh interval by lowering B:

…by a half-step (to Bb):

So, C-Bb:

…is a minor seventh interval.

The minor seventh interval is very important and is found in a wide range of chords ranging from dominant chords, to minor chords, to augmented chords, then to diminished chords.

Interval #8 – “The Diminished Seventh Interval”

The diminished seventh interval is rarely used in harmony.

It is used n the formation of the diminished seventh chord and it is two half-steps smaller than the major seventh interval.

The B major seventh interval (B-A#):

…can be lowered by two half-steps to form the B diminished seventh interval.

Lowering A#:

…by two half-steps (from A# to Ab):

…produces B-Ab:

…which is a diminished seventh interval.

Final Words

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Chuku Onyemachi

Head of Education at HearandPlay Music Group
Onyemachi "Onye" Chuku (aka - "Dr. Pokey") 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.