The Octatonic Scale: Eight Tones Per Octave

Today, we’ll be studying the octatonic scale.

Understanding the term octatonic as an eight-tone scale won’t be difficult if you’re familiar with prefixes.

Oct, for the most part, represents eight. Think of the octopus, and even the octave. What do they all have in common? Answer is eight.

In this post, we’ll get started with the octatonic scale. But before that, let’s review two melodic progressions that we’ll certainly need in the formation of the octatonic scale.

Review of Melodic Progressions

Melodic progressions are a product of the division of the octave into a certain number of equal parts.

Further reading: Six Common Melodic Progressions.

The two melodic progressions we’ll use in the formation of the octatonic scale are the semitone (aka – “half step”) and the whole tone (aka – “whole step”).

Semitone

The octave is naturally divided into twelve equal parts called semitones.

From one note on the piano to an adjacent note, whether white or black is a semitone (or half step). For example…

C to C#:

C# to D:

D to D#:

D# to E:

All the semitones so far have been from a white note to a black note or vice versa. However, in the case of E to F:

…it’s between two adjacent white notes. If you keep moving from one note to its adjacent note, you’ll derive the rest of them.

Permit me to use the term half step instead of semitone from this point on.

Whole tone

A distance of two semitones is equal to one whole tone.

To determine a whole tone from C, count two semitones:

1^st semitone (C to C#):

2^nd semitone (C# to D):

Therefore C to D:

…is a whole tone.

Other whole tones include…

C# to D#:

D to E:

There are even whole tones like E to F#:

…from a white note to a black note.

The reverse is the case for Eb to F:

…where it’s a black note to a white note.

I’ll also prefer to use the term whole step to substitute for whole tone from this point on.

Note: Beyond this point in this post, your understanding of our subject – the octatonic scale – will depend on your understanding of these two melodic progressions: semitone (half step) and whole tone (whole step).

Scale Formation Of The Octatonic Scale

One of the ways of classifying scales is according to the number of notes they have per octave (aka – “note aggregate”).

In the octatonic scale, there are eight notes within the compass of one octave versus the regular seven notes per octave in the major and minor scales (Note: Don’t include the higher “C” in your calculation as that’s considered the next octave).

C major scale:

C minor scale

…or five notes per octave in the case of the pentatonic scale:

C major pentatonic

Formation of the octatonic scale is by alternating half steps and whole steps (which are the two melodic progressions we just covered in the last segment) from any note until an octave is reached.

There are two variants of the octatonic scale:

1. Octatonic whole half
2. Octatonic half whole

Check them out below.

Octatonic “Whole-Half” Scale

This variant of the octatonic scale is built off half steps and whole steps that are alternated in this order:

Whole step + Half step + Whole step + Half step etc., and that’s pretty much where the name “whole-half” comes from.

Starting from C, you can alternate whole steps and half steps until the octave is reached.

C + whole step = D:

…then we add a half step to D.

D + half step = D#:

…then we add a whole step to D#.

D# + whole step = F:

…then we add a half step to F.

F + half step = F#:

…then we add a whole step to F#.

F# + whole step = G#:

…then we add a half step to G#.

G# + half step = A:

…then we add a whole step to A.

A + whole step = B:

…then we add a half step to B.

B + half step = C:

At this point, an octave is reached. Here’s the C octatonic “whole-half” scale:

The octatonic “whole-half” scale is so called because of the order of the melodic progressions it’s built off.

Below are octatonic “whole-half” scales in all keys:

C octatonic whole-half:

C# octatonic whole-half:

…similar to Db octatonic whole-half.

D octatonic whole-half:

D# octatonic whole-half:

…similar to Eb octatonic whole-half.

E octatonic whole-half:

F octatonic whole-half:

F# octatonic whole-half:

…similar to Gb octatonic whole-half.

G octatonic whole-half:

Ab octatonic whole-half:

…similar to G# octatonic whole-half.

A octatonic whole-half:

Bb octatonic whole-half:

…similar to A# octatonic whole-half.

B octatonic whole-half:

Octatonic “Half-Whole” Scale

This is another variant of the octatonic scale.

From its name, you can tell that the half steps and whole steps are alternated in this order:

Half step + Whole step + Half step + Whole step etc.

Starting from C, you can alternate half steps and whole steps until octave is reached. Here you are:

C + half step = C#:

…then we add a whole step to C#.

C# + whole step = D#:

…then we add a half step to D#.

D# + half step = E:

…then we add a whole step to E.

E + whole step = F#:

…then we add a half step to F#.

F# + half step = G:

…then we add a whole step to G.

G + whole step = A:

…then we add a half step to A.

A + half step = A#:

…then we add a whole step to A#.

A# + whole step = C:

At this point, an octave is reached. Here you are with C octatonic “half-whole” scale:

The octatonic “half-whole” scale is so called because of the order the melodic progressions it’s built off.

Below are octatonic “half-whole” scales in all keys:

C octatonic half-whole:

C# octatonic half-whole:

…similar to Db octatonic half whole.

D octatonic half-whole:

D# octatonic half-whole:

…similar to Eb octatonic half whole.

E octatonic half-whole:

F octatonic half-whole:

F# octatonic half-whole:

…similar to Gb octatonic half whole.

G octatonic half-whole:

G# octatonic half-whole:

…similar to Ab octatonic half whole.

A octatonic half-whole:

Bb octatonic half-whole:

…similar to A# octatonic half whole.

B octatonic half-whole:

Final Words

Some experience players may recognize these two scales as the “diminished scale.” You’ve just learned the whole-half diminished scale along with the half-whole variation.

Remember, the octatonic scale has eight notes per octave.

Considering that there are only seven letter names in music, this means that repetition of letter names is allowed in its spelling.

C octatonic “half-whole” can be spelled as:
C C# D# E F# G A Bb C

Can you see the repetition of the C (C and C#):

…at the beginning of this scale?

Did you also notice that sharp and flat symbols are used freely?

It’s even possible to have various spellings of this octatonic scale. Here are some of them:

I can’t wait to show you the application of the octatonic scale in a future post (I’ve already given you a hint… “diminished”).

See you then!

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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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