Introduction
In Jazz, it’s possible to use many different scales over a single chord. This is one of the things that makes Jazz interesting to listen to. You don’t just hear a plain old C Major scale over a CMaj7 chord, which is a bit unimaginative. Instead you might hear a C Lydian Augmented scale (we will cover this scale in the next lesson), which is far more enticing.
But why can we use multiple scales over the same chord? And how do we pick those scales? If the chord progression is in a single key, how is it possible to use different scales from different keys?
Playing IN and FROM a key
To answer these question we must understand the difference between playing IN a key and playing FROM a key – a very important distinction.
Generally, songs are written IN a major or natural minor key. But you can play scales and chords FROM a different key.
Take the chord CMaj7. It can be derived both FROM the key of C Major and G Major (C Lydian). Another way of saying this is that all the notes in the chord CMaj7 can be found in both the C Major Scale and the G Major Scale. Therefore you can use both scales to improvise over this chord.
| Scale | Notes | CMaj7 Chord | Comment |
|---|---|---|---|
| C Major | C D E F G A B | I | Notes in CMaj7 chord are all found in both the C Major and G major Scales |
| G Major | G A B C D E F# | IV |
Why You Can Use Multiple Scales Over the Same Chord
So that means, when improvising, you can use any scale over a particular chord, as long as that scale has all the notes found in that particular chord.
This works even if the whole progression is in a particular key. For example, if we take a II-V-I in C Major:
| Comments | II | V | I |
|---|---|---|---|
| - Chord Progression is IN the key of C Major - All chord are FROM the key of C Major | Dm7 | G7 | CMaj7 |
| - Chord Progression is IN the key of C Major - II-V are FROM the key of C Aeolian | Dm7♭5 | Gm7 | CMaj7 |
- Even though the top chord progression is IN the key of C Major, we can still use the C Lydian scale (G Major) to improvise over the CMaj7 chord.
- We encountered a similar idea when we discussed Modal Interchange. Even though a chord progression can be IN the key of C Major, we can still use (borrow) chords FROM a different key. In the case of the bottom chord progression, we borrowed the II-V chords from the key of C Aeolian (E♭ Major).
But using scales over chords is actually a little bit more complicated than this.
Omitting and Changing Notes
We have already discuss (many times) that the most important notes of a chord are the Guide Tones (3rd & 7th) and to a lesser extent the root (which establishes tonality). The 5th is dispensable. This means you can play any scale over a chord, if that scale contains the root, 3rd and 7th of the chord. For example, you can use any scale with a C, E and B in it over a CMaj7 chord, even if it doesn’t contain a G.
There are two further complication:
- It’s possible to omit notes; and
- It’s possible to treat notes enharmonically (i.e. as a different chord degree).
If a scale has BOTH a minor 3rd and a Major 3rd – the Major 3rd is the True 3rd and the minor 3rd is actually a disguised #9. And it is possible for a scale to omit the 3rd or 7th of a chord and yet still work over that chord – the 3rd or 7th is implied by the harmony. Some examples will make this clearer.
Let’s take the C7 chord and see what scales we can use to improvise over it.
| Scale | Degrees | Comments |
|---|---|---|
| C Dominant Bebop scale | 1 2 3 4 5 6 ♭7 7 | Maj 7 used as passing note |
| Whole-tone scale | 1 2 3 ♭5 ♭6 ♭7 | 1, 3 & ♭7 |
| Altered scale | 1 ♭2 ♭3 ♭4 ♭5 ♭6 ♭7 | ♭3 = #2 = #9 ♭4 = 3 |
| Blues scale | 1 ♭3 4 #4 5 ♭7 | ♭3 = #2 = #9 Omits 3 |
- The C Dominant Bebop scale fits perfectly over a C7 chord because it starts on the root (C) and has the 3 and ♭7. The ♮7 acts only as a passing note.
- The C Wholetone scale fits perfectly over a C7 chord because it starts on the root (C) and has the 3 and ♭7.
- The C Altered scale also fits over a C7 chord even though it has a ♭3 (E♭). This is because the ♭3 acts as a #9 (D#) and the True 3rd is the ♭4 (E). So the♭3 is enharmonically the same as a #9 and the♭4 is enharmonically the same as a♮3. So actually, this scale fits rather well over a C7 chord.
- The C Blues scale also fits over a C7 chord. The♭3 is treated as a #9 and the♮3 is omitted. The♮3 is implied by the chord C7. So then the scale has an implied♮3 and a ♭7, so fits over C7 perfectly well.
(Aside #1: The ♮3 always overrides the minor ♭3 and turns it into a #9. This generally only applies to V7 chords and works because the #9 is an available tension over a C7 chord).
(Aside #2: This idea does NOT apply to 7ths. You cannot turn a♭7 into a #6 or #13. This is because a #13 is not an available tension over any chord).
Conclusion
Over the next few lessons we will cover a number of commonly used Jazz Scales. We will learn how they are derived and the chords they are associated with. But now we know why we can use many different scales over a single chord, and this knowledge will help us analyse the upcoming scales. In the mean time, below is a selection of scales that can be used over particular chords, precisely because they share the root, 3rd and 7th of the chord.
| Chord | Possible Scale | Degrees | From C |
|---|---|---|---|
| Major 7 (any scale with Maj 3 & Maj 7) | Ionian | 1 2 3 4 5 6 7 | C D E F G A B |
| Lydian | 1 2 3 #4 5 6 7 | C D E F# G A B | |
| Lydian Augmented | 1 2 3 #4 #5 6 7 | C D E F# G# A B | |
| Major Bebop Scale | 1 2 3 4 5 ♭6 6 7 | C D E F G A♭ A B | |
| Minor 7 (any scale with min 3 & min 7) | Aeolian | 1 2 ♭3 4 5 ♭6 ♭7 | CD E♭ F G A♭ B♭ |
| Dorian | 1 2 ♭3 4 5 6 ♭7 | C D E♭ F G A B♭ | |
| Phrygian | 1 ♭2 ♭3 4 5 ♭6 ♭7 | C D♭ E♭ F G A♭ B♭ | |
| Half Diminished (any scale with min 3, ♭5 & min 7) | Locrian | 1 ♭2 ♭3 4 ♭5 ♭6 ♭7 | C D♭ E♭ F G♭ A♭ B♭ |
| Half-diminished | 1 2 ♭3 4 ♭5 ♭6 ♭7 | C D E♭ F G♭ A♭ B♭ | |
| Dominant 7 (any scale with Maj 3 & min 7) | Mixolydian | 1 2 3 4 5 6 ♭7 | C D E F G A B♭ |
| Lydian Dominant | 1 2 3 #4 5 6 ♭7 | C D E F# G A B♭ | |
| Mixolydian b6 Scale | 1 2 3 4 5 ♭6 ♭7 | C D E F G A♭ B♭ | |
| Altered | 1 ♭2 ♭3 ♭4 ♭5 ♭6 ♭7 | C D♭ E♭ F♭ G♭ A♭ B♭ | |
| Dorian ♭2 | 1 ♭2 ♭3 4 5 6 ♭7 | C D♭ E♭ F G A B♭ | |
| Major Pentatonic | 1 2 3 5 6 | C D E G A | |
| Blues | 1 ♭3 4 #4 5 ♭7 | C E♭ F F# G B♭ | |
| 5th mode of harm min. | 1 ♭2 3 4 5 ♭6 ♭7 | C D♭ E F G A♭ B♭ | |
| 5th mode of harm Maj. | 1 ♭2 3 4 5 6 ♭7 | C D♭ E F G A B♭ | |
| Dominant Bebop | 1 2 3 4 5 6 ♭7 7 | C D E F G A B♭ B | |
| Dominant Diminished | 1 ♭2 #2 3 #4 5 6 ♭7 | C D♭ D# E F# G A B♭ | |
| Whole Tone | 1 2 3 #4 #5 ♭7 | C D E G♭ A♭ B♭ |