The Application Of The Octave Shrinking Technique In Chord Formation

In today’s lesson we’ll be looking at the application of the octave shrinking technique in chord formation.

If you understand the techniques I’ll share with you in this post, the formation of various seventh chord qualities can be done with absolute ease. Although there are various classes of seventh chords, we’ll be limiting our scope to these seven classes of seventh chords:

• The major seventh
• The minor seventh
• The dominant seventh
• The half-diminished seventh
• The minor major seventh
• The augmented major seventh
• The diminished major seventh

So let’s get started with this study by taking a look at the concept of the octave.

An Overview Of The Concept Of The Octave

Octave takes its root from the Latin word ‘octava’ which means eight. Octave literally means eight. The octave is important in music for a variety of reasons.

“Check it out…”

There are seven natural pitch classes on the keyboard from A to G:

…which is usually labeled from C to B:

…for the case of simplicity.

If you are highlighting the natural pitch classes on the keyboard, you will have these first seven notes. Beyond these seven, if you take one more step from the seventh tone, you will be getting to the eight tone – which is a duplicate of the first note that you started out from.

So from C to B:

…seven pitch classes [seven notes].

If we make it eight notes, the eighth note (which is C):

…is the octava which literally means eight of this C:

So when the term octave is used, it means that this C:

…is eight notes higher than this C:

So that’s the concept of the octave. Check out our lesson on the four dimensions of the octave.

Also take note that the octave can also be an eighth below. So the octave of this C:

…is this C:

Having reviewed the concept of the octave, let’s proceed to the octave shrinking technique.

“What Is The Octave Shrinking Technique?”

The focus of the octave shrinking technique is to make the octave smaller. Although there are so many steps to take in diminishing the size of the octave, in this lesson we’ll be taking two steps:

• Shrinking it by a half step
• Shrinking it by a whole step

An octave can be shrinked by lowering its higher pitch. For example the C octave (C-C):

…can be shrinked by lowering its higher pitch (C):

…by a half step. Lowering this C:

…by a half step (to B):

…produces C-B:

You can also shrink the C octave (C-C):

…by lowering its higher pitch (C):

…by a whole step. Lowering C:

…by a whole step (to Bb):

…produces C-Bb:

In the first case, we shrinked the octave into C-B:

…which is a major seventh. We also shrinked the octave into C-Bb:

…which is a minor seventh. Altogether, after the shrinking of the octave in both cases we came up with two important intervals…

• Major seventh
• Minor seventh

These two intervals are important in the formation of seventh chords because they are the intervallic constituents of common seventh chords.

Formation Of The Seventh Chords Using The Octave Shrinking Technique

Various seventh chords can be formed using the octave shrinking technique and I’ll be showing you how it works in this segment. We’ll be using different classes of four note triads  (aka – “octave position triads”) and shrinking them using the octave shrinking technique.

“Let me throw more light on octave position triads…”

A triad is a chord of three notes. A triad can have as much as four notes if its root is duplicated. For example, the duplication of the root (C) of the C major triad, produces its octave position:

“Let’s proceed to the derivation of various classes of seventh chords using the octave shrinking technique…”

The Octave Shrinking Of The Major Triad

The C major triad:

…when played in octave position:

…can be shrinked by a half step:

…to produce the C major seventh chord.

The C major triad:

…played in octave position:

…can be shrinked by a whole step:

…and this produces the C dominant seventh chord.

Now that we’re done with the major triad, let’s proceed to minor triads.

The Octave Shrinking Of The Minor Triad

The C minor triad:

… if played in octave position:

…can be shrinked by a half step:

…and this produces the C minor major seventh chord.

The C minor triad:

… if played in octave position:

…can also be shrinked by a whole step:

…and this produces the C minor seventh chord.

Let’s proceed to augmented triads.

The Octave Shrinking Of The Augmented Triad

The C augmented triad:

…if played in octave position:

…can be shrinked by a half step:

…and this produces the C augmented major seventh chord:

The C augmented triad:

… if played in octave position:

…can also be shrinked by a whole step:

…and this produces the C 7Aug chord.

Let’s round up by taking a look at the formation of seventh chords using diminished triads played in octave position.

The Octave Shrinking Of The Diminished Triad

The C diminished triad:

… when played in octave position:

…can be shrinked by a half step:

…to produce the C diminished major seventh chord.

The C diminished triad:

… played in octave position:

…can also be shrinked by a whole step:

…and this produces the C half-diminished seventh chord:

Final Words

We’ve been able to form several classes of seventh chords using the octave shrinking technique, and this makes it one of the tools that you need to master to form seventh chords.

Seventh chords have never sounded so easier, and I know you are taking advantage of the octave shrinking technique.

Thank you and I will see you in another lesson.

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Chuku Onyemachi

Head of Education at HearandPlay Music Group

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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Tagged as: augmented major seventh, augmented triad, diminished major seventh, diminished triad, dominant seventh, formation of seventh chords, four note triads, half-diminished seventh, major seventh, major triad, minor seventh, minor triad, minor-major seventh, octave, octave shrinking, triads