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Chord Construction : 4) Minor triads and 7ths
Bernard McDonagh

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Each Major key has a ‘Relative Minor' key, and each Minor key it's ‘Relative Major'. They are ‘relative' to each other because they share the same key signature. Just as we form chords from the Major scale, so we can also form them from the Relative Minor scale.

We can find the Relative Minor key in one of two ways: 1) go down three letter names from the Major key tonic, e.g. if the tonic is C, then go down three steps in the scale from C to A, or 2) go up to the sixth degree of the Major scale, again from C to A. Obviously, if we go up three letter names from the Minor scale tonic it will lead us to the Relative Major key.

Scale

C

D

E

F

G

A

B

C

Degree

I

II

III

IV

V

VI

VII

VIII

Just as each Major key is derived from it's Major scale, so also are the Minor keys derived from this ‘Relative Minor' scale. As we have seen, to find the Relative Minor key and the scale from which it is formed, we simply go up or down to the sixth degree of the Major scale. In the key of C Major this of course will lead us to ‘A' Minor. It has the same notes as the C Major scale, but now starts and finishes on ‘A'. This scale is called the ‘A Natural Minor' scale.

Scale

A

B

C

D

E

F

G

A

Degree

I

II

III

IV

V

VI

VII

VIII

C Major and A Minor have the same key signature because they share common scale tones, and both have no sharps or flats. The keys of G Major and E Minor have one sharp, while D Major and B Minor have two sharps. B b Major and G Minor have two flats, etc.

If the C Major and A Natural Minor scales have the same notes, they will obviously also have the same chords when harmonized. Of course the big difference is that what was a degree VI minor chord in C Major, is now the tonic or number I chord in the key of A Minor.

KEY OF C MAJOR

CMA7

DMI7

EMI7

FMI7

G7

AMI7

BMI7b5

I

II

III

IV

V

VI

VII

KEY OF A MINOR

AMI7

BMI7b5

CMA7

DMI7

EMI7

FMA7

G7

I

II

III

IV

V

VI

VII

These chords are diatonic in the key of A Minor. The Minor 7 flat 5 chord is not common in a major key, yet it is common in a minor key, where it is the II (two) chord.

In a major key, we know that degrees I, IV and V all give us major triads. (When the 7ths are added you'll remember that degree V becomes a Dominant chord.) In minor keys, degrees I, IV, and V all produce diatonic minor triads. In the case of minor keys, this is the all important factor which led to the creation, by composers, of alternative minor scales to the Natural Minor.

It's all about cadences. A ‘cadence' is an ending or resting place for a musical phrase or passage. For example, a common major key cadence would be to go from G7 to a C chord, while the melody may go from B up to the tonic, C, or go down from F to the third, E, etc. Upon listening you will immediately understand the sense of completeness or balance this gives to the music.

Around the beginning of the Baroque period (early 1600's) composers decided that a minor chord on degree V was not providing a strong cadence. For example, in the key of A Minor, going from the V chord, E minor , back to the A minor tonic just wasn't ‘complete' sounding or properly resolved. They wanted something which would give them the desired cadence.

What they did was to create a stronger, more convincing resolution in their music by using a major triad or dominant 7th chord on the fifth degree. Now the cadence would be from E or E7 back to A Minor, and so on. To obtain this they created a scale that provided it: the ‘Harmonic' Minor scale'.

To create this scale, the seventh degree of the Natural Minor scale is raised a semitone, resulting in the desired chords on degree V.

The A ‘Harmonic Minor' scale

Scale

A

B

C

D

E

F

G#

A

Degree

I

II

III

IV

V

VI

VII

VIII

When we harmonize the Harmonic Minor scale, degree V now gives us the notes E – G# – B, which is an E major triad. An E7 chord follows by adding an additional 3rd interval above the B, which of course is a D.

Check out what happens to rest of the chords with the Harmonic Minor's raised 7th degree:

Scale Degrees

Notes

Resulting Chord

Written as

 

 

 

 

1 - 3 - 5

A - C - E

A minor

AMI

2 - 4 - 6

B - D - F

B diminished

3 - 5 - 7

C - E - G#

C augmented

C(#5)
or C+

4 - 6 - 8

D - F - A

D minor

DMI

5 - 7 - 2

E - G# - B

E major

E

6 - 8 - 3

F - A - C

F major

F

7 - 2 - 4

G# - B - D

G# diminished

G#°

Note : The chord with a #5 (a ‘sharp' or raised 5th) is widely known as an ‘Augmented' chord, and has a ‘+' symbol, such as the C+ above. There is a Dominant #5 chord as well; for example, C7(#5), or Bb7(#5), which can also be written as C7+, or Bb7+. An ‘augmented' 5th is really the name for an interval, so perhaps ‘#5' is more accurate when naming chords. However both names are widely used.

The vast majority of the “Classical” music repertoire, from the 17th to the 20th centuries, is dominated by the Harmonic Minor scale; at least, in terms of harmony. However, this scale is still the most prevalent one in most other music in minor keys too.

Despite that, contemporary popular music, Jazz, Blues, and various world / roots music forms have also continued to use the Natural Minor scale, as well as the Harmonic Minor.

Here are the 7 th chords that result from the harmonization of the Harmonic Minor scale:

Scale Degrees

Notes

Resulting Chord

Written as

 

 

 

 

1-3-5-7

A-C-E-G#

A minor / major 7th

AMI(ma7)

2-4-6-8

B-D-F-A

B minor 7th flatted 5th

BMI7(b5)

3-5-7-2

C-E-G#-B

C major 7th sharp 5

CMA7(#5)

4-6-8-3

D-F-A-C

D minor 7th

DMI7

5-7-2-4

E-G#-B-D

E dominant 7th

E7

6-8-3-5

F-A-C-E

F major 7th

FMA7

7-2-4-6

G#-B-D-F

G# diminished 7th

G#°7

The chord on the first degree is an interesting one. It's an A Minor triad with a major 7 th . You have probably heard something similar to this:

 AMI       AMI(MA7)   AMI7       DMI7 
| / / / / | / / / / | / / / / | / / / / | 

I think I've seen more blue moons than I have Major7th (#5) chords, but they're out there! The diminished chords are fascinating chords, but we don't have to thank the Harmonic Minor scale alone for their existence, as they are also formed from the Diminished Scale. It's clear then, that the ‘Harmonic Minor' scale's most useful feature is the Major triad or Dominant chord formed on degree 5.

There are other fascinating Minor scales too. However they are used for making melody, not harmony. They include the Melodic Minor scale, Pentatonic Minor scale, and the various minor modes derived from the Major scale.

 

Click here for our course on harmony

© 2004 Bernard McDonagh
Email : author@gsus.biz
http://www.gsus.biz


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