The Altered Scale – The Complete Guide
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One of the most interesting improv scales you’ll encounter in jazz theory is that of the Altered Scale. This vexing 7-note scale can be a bit confusing, but it is without question one of the hippest jazz scales you can play. In today’s Quick Tip, The Altered Scale—The Complete Guide, John Proulx breaks down exactly what this scale is and how to use it to improvise like a pro. You’ll learn:
- What is the Altered Scale?
- 3 Easy Tips for Constructing Altered Scales
- Chord Symbols for the Altered Scale
- When to Use the Altered Scale
- 5 Must-Have Jazz Licks with the Altered Scale
If you typically freeze when you see the chord suffix “alt” in a fake book, then this lesson is for you!
Intro to the Hippest Jazz Scale
Jazz pianists often favor the unmistakable dark and complex sound of the altered scale to add additional tension when improvising over dominant 7th chords. Check out the following example:
Today’s lesson is all about how you can improvise with this unique jazz improv scale. The lesson sheet PDF is downloadable from the bottom this page after logging in with your membership. In addition, PWJ members can easily change the key of the lesson sheet using our Smart Sheet Music.
The Altered Scale (aka “altered dominant scale”) is used by jazz musicians to create tension and dissonance when improvising over dominant 7th chords. The sound of the Altered Scale is unique for several reasons. Firstly, it packs all of the possible altered dominant scale tones (♭9, ♯9, ♭5, ♯5) into a single scale. Secondly, it contains both a minor 3rd and a major 3rd. Thirdly, the first five notes are identical to a Half-Whole Diminished Scale while the last five notes are identical to a Whole Tone Scale. The scale formula for the Altered Scale (as compared to a major scale) is 1–♭2–♭3–♭4–♭5–♭6–♭7 and the intervallic construction is H–W–H–W–W–W–W. Other common names include the Diminished Whole-Tone Scale, the Super Locrian Mode and the Melodic Minor 7th Mode.
C Altered Scale
The name “Altered Scale” is short for Altered Dominant Scale. This tells us that this scale is used over dominant 7th chords and that it is characterized by altered dominant scale tones, also known as chord alterations (♭9, ♯9, ♭5, ♯5 or ♭9, ♯9, ♯11, ♭13 enharmonically).
The Altered Scale has several other names that are common among jazz musicians. In fact, each name helps us to understand the scale in a slightly different way.
#1: Altered Dominant Scale
This name is straightforward and simple, describing both the scale’s function (dominant) and its tonal characteristics (altered). In fact, musicians who use the name Altered Dominant Scale most likely think of the scale as 1–♭9–♯9–3–♭5–♯5–♭7. In other words, they see the root, the guide tones and the alterations. The following example compares a traditional Dominant Scale (aka Mixolydian) with the Altered Dominant Scale. Notice that we’ve enharmonically renamed the scale tones of the Altered Scale to make it easier to visualize its function and tonal characteristics.
#2: Diminished Whole Tone Scale
Another popular name for our focal scale is the Diminished Whole Tone Scale. That’s because the first five notes are identical to a Half-Whole Diminished Scale while the last five notes are identical to a Whole Tone Scale. Of course, this is not a 10-note scale, so these scale fragments actually overlap in the middle. This name is important because it helps us understand the different melodic characteristics contained within the scale.
#3: Melodic Minor 7th Mode
Perhaps you’re wondering, “Where does the Altered Scale come from?” This scale’s unique intervallic pattern is not random at all—it is a mode. The parent scale or sources scale is the Melodic Minor Scale (the ascending version). In fact, if you play any melodic minor scale beginning on the 7th scale tone, the resulting intervallic pattern is the Altered Scale. Understanding this relationship can significantly simply the landscape when learning Altered Scales because an ascending melodic minor scale only differs from a major scale by one scale tone—the ♭3. The complete formula for an ascending melodic minor scale is 1–2–♭3–4–5–6–7.
Often times, when jazz musicians see a dominant 7th chord like C7alt, they simply think of the melodic minor scale that is a ½ step above the root of the dominant chord. Another way of saying the same thing is if you see C7alt, find the ♭9 (the note D♭) and play a melodic minor scale from there.
#4: Super Locrian Mode
The Altered Scale is also called the Super Locrian Mode, particularly in academic settings. This name highlights the relationship between the Altered Scale and the traditional Locrian mode, which is the 7th mode of a major scale. In fact, a Locrian scale and a Super Locrian scale only differ by one tone—the ♭4. Therefore, you may also occasionally encounter an Altered Scale by the name Locrian ♭4. The example below illustrates the similarities between C Locrian and C Super Locrian.
As we discussed in the previous section, there are many ways to think about the Altered Scale. Admittedly, it can seem like a lot to wrap your head around. Therefore, it’s always nice to have some shortcuts. In this section, we’ll give you 3 tricks that will help you quickly find the particular altered scale you need whenever you stumble across an altered dominant chord symbol.
#1: Root–3rd–7th + All 4 Alterations
One easy way to think of an Altered Scale is as the essential tones of the dominant 7th chord (R–3–♭7) plus all four alterations, the ♭9, ♯9, ♭5 and ♯5. You may also think of the alterations as ♭9, ♯9, ♯11 and ♭13. It helps if you can visualize the root and the 3rd connected by the ♭9 and ♯9. In addition, try to visualize the 3rd and the 7th connected by the whole tone scale fragment that includes the ♭5 and ♯5.
In fact, there is even a cool trick where you can approach soloing by using a pentatonic scale that contains all of the alterations. Simply play a major pentatonic scale (1–2–3–5–6) that is a tritone away from the given dominant 7th chord symbol. For example, if you see C7alt, you can play a C7 chord shell in your left hand (C–E–B♭) and improvise with a G♭ major pentatonic scale in your right hand. The five notes of G♭ major pentatonic (G♭–A♭–B♭–D♭–E♭) form the ♭5–♯5–♭7–♭9–♯9 of C7. This gives you all the alterations plus the ♭7 in your right hand—that’s a pretty good start!
Alternatively, you can also think of the minor pentatonic scale (1–♭3–4–5–♭7) built on the ♭3 of the given dominant 7th chord. This gives you the same notes in a different order. For example, the ♭3 of C7 is the note E♭. Therefore, you can improvise with E♭ minor pentatonic (E♭–G♭–A♭–B♭–D♭) over C7 to get a fully altered dominant sound. To form the complete Altered Scale, simply combine either of the pentatonic scales referenced above with the Root and 3rd of the given dominant 7th chord.
#2: Melodic Minor Scale Up a Half-Step
Another easy way to quickly land the correct notes for an Altered Scale it to go up a ½ step from the root of your given altered dominant 7th chord and play a melodic minor scale. In this case, we’re speaking of what is sometimes called the “jazz melodic minor scale” which uses the ascending melodic minor construction only, regardless of whether you are ascending or descending. For example, if you see C7alt, go up a ½ step to D♭ (or C♯) and play a melodic minor scale. Remember, the jazz melodic minor scale is just like the major scale with a ♭3. Therefore, you would play D♭–E♭– F♭–G♭–A♭–B♭–C.
#3: Major Scale Down a ½ Step with ♯Root
Another interesting method you can use to quickly find the right notes for an altered scale involves a going down a ½ step from the root of the dominant 7th chord. Then, play the notes of that major scale, but with a raised (♯) root. That probably sounds peculiar, but it will make sense as we consider an example. Using this approach, when we see the chord symbol C7alt, we would go down a ½ step from the root of C7alt. That means we’ll think of a B major scale (B–C♯–D♯–E–F♯–G♯–A♯), but we’ll start it on B♯ (or C♮ enharmonically) instead of B♮ because we need to raise (♯) the root. Therefore, we get B♯–C♯–D♯–E–F♯–G♯–A♯. These notes are enharmonically equivalent to the C Altered Scale.
Admittedly, this approach is not the best path toward mastering Altered Scales because you’re not truly thinking in terms of the actual altered dominant chord. Nonetheless, this can be a helpful start.
You might even be wondering how this method works at all?! Remember, we said earlier that the formula for an Altered Scale is every note flatted except the root: 1–♭2–♭3–♭4–♭5–♭6–♭7. Well, you can also get the same intervallic pattern by raising the root while leaving every other note natural: ♯1–2–3–4–5–6–7. However, raising the root actually transposes the scale upward by a ½ step. That’s why we have to go down a ½ step first.
Now that you know what an Altered Scale is and what it sounds like, let’s examine the chords symbols that are associated with this sound. The chord symbol that most commonly represents this sound is the chord suffix alt. Therefore, if you see C7alt, that is your cue to play the C Altered Scale. Of course, the suffix alt is short for “altered.” Remember, the complete chord symbol is technically C7(♭9♯9♭5♯5) or C7(♭9♯9♯11♭13). Not only is there rarely room to fit such a chord symbol, it is also slow and clumsy to read. Instead, the suffix alt allows jazz musicians to quickly read and recognize the chord/scale relationship.
Besides the suffix alt, there are several other chord symbols associated with the Altered Scale. Specifically, the ♯9♭13 combination, such as C7(♯9♭13), also represents the Altered Scale. In fact, most situations in which a chord symbols contains two alterations, the Altered Scale will be your first or second scale choice. Sometimes, the Altered Scale also works when there is only one altered note indicated in the chord symbol. Remember, the Altered Scale does not contain the ♮5, therefore a chord symbol with an altered 5th will often imply the Altered Scale. This includes symbols such as C7(♭5) or C7(♯5). The latter symbol may also be expressed as C7+, C+7 or Caug7. Earlier, we mentioned that a unique characteristic of the altered scale is that it contains both a minor 3rd (the ♯9) and a major 3rd. Therefore, the Altered Scale will often work with Dominant 7♯9 chords, such as C7(♯9).
Did you notice that the 5th was omitted in each of the chords above? That’s because the natural (♮) 5th is not included in the Altered Scale. In addition, you should not play a ♮9 or a ♮13 in your chord voicing when using this scale.
Be sure to check out our comprehensive course on Altered Dominant Rootless Voicings (Int) to learn additional left hand voicings for altered dominant chords.
Many jazz musicians favor the sound of the Altered Scale because of the strong tension that it creates over dominant 7th chords. After all, the main purpose of dominant 7th chords is to supply harmonic tension that then gives way when the chord resolves. Altered dominant chords simply add more tension.
Once you become fluent with the Altered Scale, you can actually use it over regular V7 chords too. In other words, you don’t have to see C7alt (or any of the various other altered chord symbols) to use the Altered Scale. What’s more important is that you resolve the scale to a chord tone (R-3-5-7) of the tonic chord. In addition, the 9th is also a good target note over the tonic chord, whether major or minor.
One of the best ways to learn how to improvise with the Altered Scale is by imitation. Therefore, we’ve included 5 must-have jazz licks that draw on the altered sound. For each lick, we’ll practice resolving to major and minor tonic chords. After playing these licks, you’ll likely feel much more comfortable creating your own lines.
Our first lick is known as the “Cry Me a River” lick because is drawn from the standard jazz tune by the same name. This lick features a descending melodic line beginning on the ♯9 and ending on the 5th of the tonic chord. The examples below are representative. However, jazz musicians will often play this essential melodic shape with other rhythmic variation as well.
“Cry Me a River” Lick (Major Resolution)
“Cry Me a River” Lick (Minor Resolution)
Our next lick is the “Reverse ‘Cry Me a River’ Lick.” Like the previous example, this lick begins on the ♯9 and ends on the 5th of the tonic chord. However, this reverse version has an ascending shape.
Reverse “Cry Me a River” Lick (Major Resolution)
Reverse “Cry Me a River” Lick (Minor Resolution)
Next, we have the “A Night in Tunisia” / “I’m a Foot to Want You” Lick, named after two jazz standards that featured this melodic shape.
“A Night in Tunisia” / “I’m a Fool to Want You” Lick (Major Resolution)
“A Night in Tunisia” / “I’m a Fool to Want You” Lick (Minor Resolution)
The following pair of licks demonstrate how the Altered Scale can be used over a 2-5-1 chord progression resolving to major or minor. First, we’ll consider an ascending example. Then, we’ll play a descending example.
Ascending 2-5-1 Lick (Major & Minor Resolution)
Descending 2-5-1 Lick (Major & Minor Resolution)
Lastly, we have two scalar examples. Since the scale only has 7 notes, an additional note is needed to complete an entire measure. In our first example, John creates an extra note by starting on the ♯9 before ascending from the root of the scale. Note, these example features a straight 8th-note feel.
Ascending (Major & Minor Resolution)
In the second example below, John starts by descending from the root. In this case, he adds an extra note at the end of the measure. The added note that John uses is B♮, which not in the scale. However, it is a chromatic neighbor note to the resolution note C in the following measure and forms part of an enclosure.
Descending (Major & Minor Resolution)
Congratulations, you’ve completed today’s jazz piano lesson. Hopefully, you feel much more confident about how to use this hip jazz improv scale. You may even want to bookmark this lesson in your web browser for future reference, since the alt chord symbol comes up a lot in jazz standards.
If you enjoyed this lesson, then be sure to check out the following PWJ resources:
- Jazz Piano Improv with the Melodic Minor Scale (Int/Adv)
- Learn 3 Exercises to Improvise Minor Jazz Piano (Int/Adv)
- 5 Jazz Scales for Dominant 7th Chord Improv (Int/Adv)
- Upper Structure Triads–The Ultimate Chord Hack (Int)
- Improvise Jazz Piano with Upper Structure Triads (Int/Adv)
- Piano Musical Modes–The Complete Guide (Int)
Thanks for learning with us today! We’ll see you next time.
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Michael LaDisa graduated from the University of North Texas with a major in Music Theory & Composition. He lives in Chicago where he operates a private teaching studio and performs regularly as a solo pianist. His educational work with students has been featured on WGN-TV Evening News, Fox 32 Good Day,...
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