Altered Beast: A Brief Guide to the Altered Scale

This article was originally published in 2014 and has been updated for 2022.

This is a brief guide to the altered scale – how you can figure it out and some basic harmonies derived from it. The altered scale is a mode of the melodic minor and has some notoriety within jazz circles for improvising over dominant 7 chords, particularly in minor keys.

The name comes from each scale degree being “altered” compared to the major scale – in-fact all six of the seven scale degrees are flattened.

During the 1940s and 50s but particularly from the ’60s onwards, using a scalic approach to improvising became popular with some jazz musicians over using extended chord tone arpeggios and blues licks.

That’s not to say that these approaches went out of existence – this is just an anecdotal observation about trends in jazz music.

The Major Scale

We’re going to look at the altered scale in C so we’ll start by looking at the C major scale. This is a nice and easy scale to learn because it’s just the white notes on the keyboard stretching between two Cs an octave apart. All major scales follow the same pattern: tone, tone, semitone, tone, tone, tone, semitone.

The altered scale is a mode of the melodic minor scale built on Db, so let’s look at Db major before moving on. This is the same pattern as the above notes (tone, tone, semitone, tone, tone, tone, semitone), but starting on Db, the black key directly above C.

The Natural Minor Scale

Next, we’ll use the above Db major scale and figure out the natural minor scale, or sometimes called the aeolian mode. We can use the same notes as above and flatten the third, sixth and seventh degrees. This is by far the most common minor scale you will come across.

As you can see there is a few oddities here: the Fb and Cb throw a lot of people as these aren’t naturally found on the keyboard. These are enharmonically E and B natural respectively. There’s also a double flat; Bbb. This is enharmonically the same as A natural, as in Bb, flattened again. You might find it easier to think about these as the C# natural minor scale: this is enharmonically the same scale but has fewer accidentals (flats and sharps) and no double accidentals.

The Melodic Minor Scale

The melodic minor is different type of minor scale where the sixth and seventh degrees are the same as the major scale. Or, to look at it differently, the melodic minor is the same as the major scale with just a flattened third degree.

Anybody who has learned classical music might have learned the melodic minor as different scales ascending and descending. There is reason behind this but it’s generally considered to be an anachronism when thinking about modern/pop/jazz music; when the melodic minor is mentioned it’s assumed to be just the ascending version.

The Altered Scale

I’ve mentioned already that the altered scale is a mode of the melodic minor. A mode is when we take a series of notes in a scale and start them from a different position. For example the second mode of C major would be D, E, F, G, A, B, C and D. The notes contained are identical but the emphasis and chord tones derives from them are different.

The altered scale is the seventh mode of the melodic minor, so if we started our Db melodic minor from the seventh degree (C) and ended it there too, we’d get C altered. The scale is so called because every degree is “altered” from the major.

Below is a simpler spelling of the above, we think about the Fb as an E natural (major third), the D# as a raised second degree (enharmonically minor third). Ordinarily it avoidable to mix sharps and flats in scales but this is a fine exception.

While the third degree of the scale is a minor third above the root there is also a major third (or flattened fourth if we’re being pedantic). The seventh degree of the scale is also flat – a minor seventh above the root, so we think about the altered scale as a dominant scale: a major scale with a minor seventh. For this reason it is great over dominant 7 chords in particular in a minor scale. For example C altered would be suitable over a C7 chord resolving to F minor.

Altered Chord Voicings

We established earlier the altered scale is dominant voicing. Here are some examples of C7 shell voicings (chords without a natural fifth). The #11 and b5 technically contain the same note (F#/Gb), however different contexts may call for one or another. The same is true of the #5 and b13 (or b6) – these are G# and Ab respectively.

Here are some of those voicings resolving to F minor shapes.

Lastly here are some altered voicings using two upper extensions. It’s possible to build a plethora of altered chords by voicing major triads built on the b5 and b6 degrees (Gb and Ab in the case of C altered). Experimenting with different inversions will change the top note, leading to different resolutions to tonic chords.

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