The Octatonic Scale - A Secret Weapon for Composers

If you're a composer looking for fresh and unique harmonic colors, the octatonic scale might be a great choice! Many composers have used this scale widely in jazz, film scores, and classical music. Although it's not "new," the sounds we get from it often sound ambiguous or mysterious to our ears.

But what exactly makes the octatonic scale so special? In this article, we'll dive into its unique properties and explore it from a Diatonic point of view and through the lens of Interval Theory.

1. What Is the Octatonic Scale?

Most of the scales we use in Western music contain seven tones. This includes the seven modes (Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, and Locrian). We refer to those scales as heptatonic scales. The octatonic scale is different because it consists of eight notes. Because of that, we call it the octatonic scale ("octa" means eight).

When we look at its structure, we can spot a simple alternating pattern. Let's count the distances between the tones in chromatic steps (or half steps), and we'll quickly get the pattern:

We can split the Ocatonic scale in half over the F#, revealing the symmetry that gives the scale a unique and recognizable sound that is balanced and full of harmonic surprises.

This symmetry is one of the strong connections to the world of polytonality, and we'll explore that later in this article, too, but before, let's highlight some more of its unique facts. 

2. A Scale with Four Equal Root Tones

How the Octatonic Scale Breaks Traditional Rules

Typically, a scale has only one root tone that defines its tonal center. But the octatonic scale doesn't play by these rules! Instead, it has four equal root notes. Let's come back to the sequence of numbers that defines the structure of this scale: 1, 2, 1, 2, and so on.

If we look at the smallest building block that keeps repeating, we end up with 1 and 2.

This pattern perfectly matches one of our root cycles, which is root cycle 3 ascending. So, the four equal root tones for the Octatonic scale, starting on the C note would be: C, E♭, F♯, and A.

What Does This Mean for You as the Composer?

Because of this unique feature, the octatonic scale doesn't feel locked into a single key. In fact, it gives you the freedom to move between different tonal centers effortlessly, making it an excellent choice for film scoring, jazz improvisation, and contemporary classical music.

Simply put, you can provide lots of harmonic variation and interesting sound changes to your audience without really doing much! This makes it a very efficient tool for us composers!

3. The Three Starting Notes of the Octatonic Scale

Technically, the octatonic scale can start on any of the 12 tones, but we quickly run into duplicates because of the repeating shape. That is a consequence of the four root tones. Since we introduced this scale starting on the middle C, let's take this as our first position.

There are 12 tones in total, and our first starting position already covered four of them. So, let's start on the C#, and we'll get to four new root tones, which are: C♯ – E – G – B♭.

And here's our third starting position, which now covers the remaining tones: D – F – A♭ – B. 

So, let's remember that there are only three starting positions for the octatonic scale: 

1. C-based Octatonic Scale
2. C♯-based Octatonic Scale
3. D-based Octatonic Scale

Every starting point higher than the D note brings us back to a starting position that we covered already.

4. Why Traditional Chord Building Doesn't Work

A Different Approach to Harmony

In traditional music theory, we build chords by stacking the odd-numbered scale tones on top of each other. Here's a quick example using one of my favorite scales, the Lydian Dominant:

Now, let's arrange those tones vertically and listen to some chords, starting from a straightforward triad and moving towards a 13th chord.

Although we won't discuss the Lydian Dominant in this article, we've picked it for a reason. It also connects to polytonality and, therefore, works nicely together with the Octatonic scale.

But here comes the dilemma! Let's apply this concept to the Octatonic scale and pick the odd-numbered scale tones for harmony:

As we can see, we run into diminished chords every time. So, this approach is not usable with the Octatonic scale. That's because the symmetrical structure of the scale naturally leads to diminished triads and dominant chord relationships. So, we play only combinations of the root tones from the root cycle 3.

As a result, we end up with lots of "3+3" structures! The numbers represent the vertical distances in half-steps between the notes. Simply start from the lowest note in a structure and count your way up to the next higher one. From here, you start over.

"3+3"s (or diminished chords) are leading-tone structures and want to connect to other musical places, but they are not suitable as standalone chords.

To use the octatonic scale effectively, we need to think outside the box and approach harmony in a different way. The following chapter will help you get into this.

5. The Octatonic Scale and Dominant Chords

Why Does the Octatonic Scale Work So Well Over Dominant 7th Chords?

Dominant 7th chords are harmonically unstable and gravitate towards a resolution. When we compose, that's fantastic because it keeps the harmonic flow moving.

However, before we jump into dominant 7ths, let's look at the Octatonic scale from a different angle. We already know the four root tones and that they follow the root cycle 3.

That perspective also sufficiently explains the number of scale tones in the octatonic scale. We deal with four root tones, each with its own scale tone -7. So, let's connect that knowledge to the dominant 7th chords.

The octatonic scale works well with these chords because it includes the major third (4 half-steps up) and minor seventh (2 half-steps down) for each of its four root notes. This means that you can always build a dominant 7th chord no matter which root you start on, and the structure stays the same.

A Simple Example

The dominant 7th chord consists of:

• The Root
• The major third (4 half-steps above the root)
• The minor seventh (2 below the root) 

Here are all four dominant 7th-chords:

You'll see that some notes in the example above show up enharmonically. We did this to show how these tones relate to their root tones. If we switch through the four roots available within the octatonic scale, the dominant chord structure remains intact! 

This is why jazz musicians love using the octatonic scale to create tension over dominant chords—it allows for effortless chromatic movement and interesting sounds.

Furthermore, we can also use straightforward major and minor triads on each of the root and also go into more complex extended chords, like b9-chords.

However, keep in mind that the concept of using the odd-numbered scale tones for harmony doesn't apply to the octatonic scale.

6. How to Use the Octatonic Scale in Your Compositions

Now that we know many things about the octatonic scale, it's time to put things into action and show how to compose with it.

Try This Exercise

1. Play a dominant 7th chord (e.g., C7) and improvise using the octatonic scale.
2. Experiment with switching between its four root notes and notice how the harmony shifts.
3. Try composing a short piece using the scale and explore its symmetrical nature.

This will help you get comfortable with its unique sound and will let you incorporate it into your writing.

Example - The Octatonic & Piano Exercises

You can really run through the whole scale on top of any of the four root tones. I suggest you keep the bass structure to dominant 7th chords and create a pattern above.

This procedure leads to quick piano exercises that will help you get familiar with the sound of the octatonic scale. Furthermore, you can use these building blocks as part of a sketch that you can orchestration later.

Here's an example:

These type of piano exercises are also outstanding for boosting your performance skills and warming up your fingers.

Conclusion: Why the Octatonic Scale Is Worth Exploring

The octatonic scale is a powerful and versatile tool that every composer should explore. Its symmetrical structure, multiple root notes, and strong connection to dominant harmony make it an essential scale for adding complexity, richness, and unpredictability to your music.

It can add a great and unexpected touch to your musical stories, especially if you want to explore polytonality and give your audience different ways to interpret the music you wrote.

Here is a quick summary of what you know by now and what you might try as your next steps!

Now you're ready to apply the octatonic scale to your own music and explore its unique possibilities!