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August 2009

Chord Theory, Scales And Modes

Matching Scales And Chords In Jazz

August 7, 2009

Have you ever wondered how we find out which scales to play over which chords? This article should help you. A recent comment on the site asked the question of

“How do you know which scales go with which chords?”

This is a really problematic area for many new jazz players but it need not be. The idea of finding which scale to use over which chord is actually fairly simple but confuses a lot of people. I will do some more articles on this topic in the future. For now let’s take a look at how we find out which scales to play over a simple dominant 7 chord.

Every scale can be made into a series of chords. The basic idea is that if the notes of a chord exist “in” a scale then you can play that scale over that chord. By this I mean that if all of the notes of the dominant 7 chord exist in a scale then you can play that scale over that chord. All of this sounds much more confusing than it actually is.

Let’s look at a simple example.

The notes of the C mixolydian scale are

C D E F G A Bb

The notes of the C7 chord are

C E G Bb

Look carefully at this and think hard about it. It is the essence of what we are talking about here. If you look at the C7 chord and the C mixolydian scale you will see that all the notes in the C7 chord exist in the C mixolydian scale. Because the notes of the C7 chord exist in the first chord of the C mixolydian scale we can be sure that the C7 chord defines the harmony of the mixolydian scale.

As a general rule, if you can find the notes of a chord in a scale then you can play that chord over that scale. For example you could also find a C9 chord (C E G Bb D) within the C mixolydian scale. Therefore you can play a Mixolydian scale over a C9 chord. All this comes down to really is knowing what chords are in a scale and also knowing which notes are in a chord. This knowledge will come with practice. If you don’t have the patience to learn all of this information then you could just learn to remember which scales go with which chords.

Let’s look at another example. You could also play the C Lydian b7 scale over a C7 chord. Let’s see why by looking at the notes of the C Lydian b7 scale and comparing them to a simple C7 chord.

The notes of the C Lydian b7 scale are

C D E F# G A Bb

The notes of a C7 chord are

C E G Bb

Again we can play the C Lydian b7 scale over a C dominant 7 chord because the Lydian b7 scale contains all the notes of a dominant 7 chord.

This is just a simple introduction to this topic and I hope it helps you get started. In the future lessons I will write out all the scales you can play over certain chords and explain this idea a bit further.

The most common scales to play over a dominant 7 chord are

C Mixolydian

C Major Pentatonic

C Lydian b7

Take your time with this idea and really think about it. Jazz theory isn’t nearly as difficult to understand as it first appears. Always think of a chord as being made up of the notes from a scale.

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