Octatonic & Altered Scales: A New Challenge

In this blog, we’re going to focus on two scales that provide an endless supply of transition tools. These magic scales are the octatonic and altered scales, and while you won’t come across them in much popular music, these scales are compulsory reading for any jazz, blues, or progressive pop and rock musicians looking for a fresh approach.

Some Basics
When & Where to Use Them?
Octatonic Scales
Altered Scales
The Scales: Everything in a Row
See also…

Some Basics

Before you get stuck into these sales, it’s important to have some basic knowledge of music theory so you understand everything that this blog covers. If you need a little help, you’ll find plenty in our blog catalogue. Just search ‘music theory’ to find all the info you need.

When & Where to Use Them?

Octatonic scales and altered scales are really common in jazz music, but also work really well in blues. However, since they are the kind of scales you have to think about, they do demand some in-depth study to master. If you play the blues and find yourself leaning on the same old licks again and again, then it can definitely be worth investing some time and energy in learning about octatonic and altered scales, because they’ll only build on your musical knowledge and help you to change things up – everything that any good musician wants, right?

Because they’re packed with so much tension (as you’ll hear later), octatonic and altered scales don’t feature in much pop and rock music. Also, you can’t just throw them into a blue or jazz lick and expect them to work since it can be difficult to say exactly what will sound good and what won’t – basically, the feel of the notes heavily depends on the musical context. It’s actually similar to what’s generally referred to as ‘playing outside’, in other words: playing outside of the key. In theory, this sounds horrible, but if you stick with it and push through to resolve it ‘within’ the key, it suddenly stops sounding wrong and gives the music a more adventurous and interesting vibe. So, how can you learn to do this? As always, by playing a lot, experimenting a lot, and listening closely.

Octatonic Scales

We’ll start with the octatonic scale. Since octo is Latin for eight, we’re talking about an eight-note scale, so one note more than a standard seven-note major scale like C, D, E, F, G, A, B. The octatonic scale is also referred to as the diminished scale or just dim scale, due to its close relationship with the diminished chord. Diminished chords are built out of four notes with a diminished third interval between each note, like Cdim (C, Eb, Gb, A): a chord that holds a lot of musical tension that wants to be resolved. There are actually only three diminished chords, because Cdim is made up of the same notes as Ebdim, Gbdim, and Adim; Dbdim, Edim, Gdim and Bbdim are all made up out of Db, E, G, and Bb; and Abdim and Bdim are both made up of Db, F, Ab, and B.

Getting back to the point, the octatonic scale can be played in one of two variations: from the top to the bottom, or from the bottom to the top. Since there are no rules, you can experiment with what sounds and works best. For example: C-octatonic (from the bottom to the top) is: C, D, Eb, F, Gb, Ab, A, B, C. In this scale, D, F, Ab and B are the leading notes, because they’re half a step down from the next note. Then the notes that follow (C, Eb, Gb, A) come straight out of the diminished chord we talked about above. The C-octatonic scale played from top to bottom is: C, Bb, A, G, Gb, E, Eb, Db, C. The Bb, G, and E are the leading notes – in this case, leading to Cdim (A, Gb, Eb, and C). The octatonic scale works best when played on the fifth step (the dominant 7th chord) and on a diminished chord.

Altered Scales

Now we’ll move onto the altered scale. This scale looks a lot like the octatonic scale, but is built out of seven notes instead of eight. Here, altered literally means altered – so none scale-specific. As with the octatonic scale, the altered scale has a close relationship with a chord: the altered chord. With an altered chord, all of the expansions of the chord have been altered. This refers to the 9th, 11th, and 13th. In this way, the 9th becomes a b9 or #9 (usually called a b10); the 11th becomes a #11; and the 13th becomes a b13. With this in mind, we’ll take a closer look at the altered scale.

The C-altered scale is: C, Db, D#, E, F#/Gb, G#/Ab, Bb, C. Looking at it with the C7 chord in mind, Db is the b9, D# is the #9 or b10, F#/Gb is the #11, and G#/Ab is the b13. The notes of the C7 chord are also there: C, E, and Bb. The fifth (in this case, the G) is usually left out because of its strong relationship with the root note. The altered scale also works really well on the fifth step to resolve back to the first step.

The Scales: Everything in a Row

Below, you’ll find the octatonic and altered scales fully notated. You can click on each image to enlarge them. If you look closely, you’ll notice that there are actually three octatonic scales. The octatonic scale is made up of alternating half and whole steps. If you start on a C with a half step, then you get: C, C#, D#, E, F#, G, A, Bb, C. Start on a C with a whole step, then you get: D, E, F, G, Ab, Bb, B, C#, D. Begin on a D with a half step, and you get: D, Eb, F, F#, A, B, C, D. This is the same scale as the whole-note C scale, but starting on a different note.