Published October 15th, 2009. © Chris Juergensen/chrisjuergensen.com. All Rights Reserved.

The Diatonic System - Understanding the diatonic system is a must if you really want to comprehend music as a whole. The system has been used for several hundred years and music is, for the most part, still based on the system. As we discussed in both the major scale and composition lesson, composers first starting harmonizing the major scale in triads starting in the 1300s (If you are already familiar with this, skip down to the lesson).

By taking every other note from the root and stacking them, we get a C major chord:

And then from the second note, we can construct a D minor chord:

When we do this for every note in the scale, we get seven triads (a triad is a three note chord):

Harmonizing the major scale in 7th Chords
Slowly but surely, composers became more harmonically daring and began harmonizing the scale not in three notes, but four. The result is 7th chords:

Here is the C major scale harmonized in 7th chords:

Our new diatonic pallet that looks like this:

Key: C

Take notice that when harmonized as triads, there are only three chord types: major, minor and diminished. But when we harmonize to 7th chords, we get four types: maj7, min7, 7 and min7b5. The more you harmonize, the greater selection of chord types you get.

It is important that you begin to internalize the diatonic pallet. It is a vital tool for melody, harmony and composition. But remember, it is important to internalize it at both a theoretic level and practical level, which is what we are about to do.

The diatonic 7th chords harmonized from major scale pattern 4

Since all these 7th chords were harmonized from the C major scale, you will find that each of them can be found inside each individual scale pattern. This lesson will deal with major scale pattern 4. For review, here it is:

The following 7ths chords can all be found in C major scale pattern 4. Now why should we learn the chord shapes inside each of the individual scale patterns? There are several good reasons:

• It will lead to good voice leading as you won't need to jump around all over the place to play the individual chords
• By being able to see the chords inside the scale, you will be able to play chord tones much easier when improvising using the scale.
• It will make you much more familiar with notes on the neck.
• You will learn some new voicings.

Here are the 7th chords from scale pattern 4 (see if you can't locate them in scale pattern 4 above):

Voicing:1,7,3,5	Voicing:1,b7,b3,5	Voicing:1,5,b7,b3,5	Voicing:1,5,7,3,5	Voicing:1,3,b7,1	Voicing:1,5,b7,b3	Voicing:1,b5,b7,b3

Applications
Practice playing the chord forms diatonic to the pattern 4 C major scale in the following progressions.

Ex.1) The following chord progression utilizes all the diatonic 7th chords in the key of C moving up in fourths from the ii chord. This is a very typical progression that surfaces in all genres of music:

Dmin7	G7	Cmaj7	Fmaj7	Bmin7b5	Emin7	Amin7

The Caged System Revisited
It is important to understand these diatonic chords not only as part of the diatonic system and derivative forms from the pattern 4 major scale but also as individual forms from the CAGED system. Both Dmin7 and Cmaj7 are based off of the E-Form. Starting with Dmin and its possible Dmin7 variations:

Voicing:1,5,1,b3,5,1	Voicing:1,5,b7,b3,5,1	Voicing:1,b7,b3,5

C and its possible Cmaj7 variations:

Voicing:1,5,1,3,5,1	Voicing:1,7,3,5	Voicing:1,3,5,7

G7 is based off of the C-Form:

Voicing:1,3,5,1,3	Voicing:1,3,b7,5

Both Fmaj7 and Emin7 are based off of the A-Form. Starting with Fmaj7:

Voicing:1,5,1,3	Voicing:1,5,7,3,5

On to the Emin and its variations:

Voicing:1,5,1,b3,5	Voicing:1,5,b7,b3,5	Voicing:1,5,b7,b3,b7

Bmin7b5 and Amin7 are based off of the D-Form from the CAGED system. Starting with the Bmin and Bmin7b5 chord:

Voicing:1,5,1,b3	Voicing:1,b5,b7,b3

And Amin and Amin7:

Voicing:1,5,1,b3	Voicing:1,5,b7,b3

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