Music Theory - Minor Keys
So far we've centered ourselves on the key of C Major and discussed all our chords and theory in terms of the major scale. Let's branch out to the minor scale.
The minor scale actually has 3 common variations: natural, harmonic, and melodic. We will only cover natural for now.
Contents
PreReqs
The Natural Minor Scale
The natural minor scale is basically exactly the same as the major scale, except the major 3rd, major 6th, and major 7th are all flattened to minor 3rd, minor 6th, and minor 7th. This changes the whole-half pattern as follows:
| m2 | M2 | m3 | M3 | P4 | d5 | P5 | m6 | M6 | m7 | M7 | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Major | x | x | x | x | x | x | |||||
| Minor | x | x | x | x | x | x |
Major: w-w-h-w-w-w-h Minor: w-h-w-w-h-w-w
Relative Minor/Major
If you observed astutely, the whole-half pattern is exactly the same; it just starts on a different note:
Major: w-w-h-w-w-w-h w-w-h-w-w-w-h Minor: w-h-w-w-h-w-w
So if you take any major key and play a scale starting on the sixth note, you have a natural minor scale. For the key of C Major, the sixth note is A. A-B-C-D-E-F-G-A is the A Minor scale.
When two scales share the exact same set of notes, they are called relatives. For any major scale, there is a relative minor and vice versa. A Minor is the relative minor of C Major.
A Minor Scale in Open Position
E---------------------------------------------- B---------------------------------------------- G-------------------0--2--0-------------------- D----------0--2--3-----------3--2--0----------- A-0--2--3-----------------------------3--2--0-- E---------------------------------------------- A B C D E F G A G F E D C B A
E-------------------------------------------0--1--3-/5-- B----------------------------------0--1--3-------------- G----------------------------0--2----------------------- D-------------------0--2--3----------------------------- A----------0--2--3-------------------------------------- E-0--1--3----------------------------------------------- E F G A B C D E F G A B C D E F G A
Playing one octave is a little new, but looking at all the notes in open position is exactly the same as C Major. Focus on playing the single octave ascending and descending.
Understanding Minor Tonality
Now, remember what we said about the major scale - the major 7th as the 7th note wants to lead into the tonic. When playing the major scale, it is as if the tonic is a gravitational force, pulling melody and harmony towards it. So how can we play the same set of notes but not get pulled towards that note?
In many respects, we do get pulled to the note; but because we are starting on the 6th note of the major scale, ascending we hit the 7th immediately, before a real tonality is established. Descending we reach the tonic note of the major scale before that 7th.
Beginning on the 6th establishes the 6th as the tonal center. This could be overridden if the melody or harmony demonstrated a goal of reaching the tonic note of the major key. Yet, without these things present, the 6th can remain the tonal center.
And remember, the scale itself isn't supposed to be a whole composition - it's simply the set of notes. Playing the scale ascending may not give us a strong resolution when we hit the tonic note, but a cleverly designed melody against a harmony that establishes the minor tonality will find a strong resolution on the tonic note.
The minor scale features a perfect 4th and perfect 5th, like the major scale, which assists in allowing it to establish its own tonality. The minor tonality may not be as strong as the major, but that's kind of the point. We want the minor key to sound different, to sound a little more tense, even when we reach the tonic note. The m3 and m6 intervals are less harmonic than the M3 and M6. On the other hand, the m7 is more harmonic than the M7. Overall, there is more dissonance, making the key less "settling".
Diatonic Chords and Harmonic Function
We will have the same diatonic chords as the relative major; however, their roman numerals are changed to represent the scale degree of the minor key:
| Chord in A Minor | Diatonic Chord Name | Parallel of | Harmonic Function |
|---|---|---|---|
| Am | i - Tonic | Tonic | |
| Bdim | ii - Supertonic | Pre-Dominant | |
| C | III - Mediant | i | Dominant/Tonic |
| Dm | iv - Subdominant | Pre-Dominant | |
| Em | v - Dominant | Dominant | |
| F | VI - Submediant | iv | Tonic/Pre-Dominant |
| G | VII - Leading | v | Dominant |
Harmonically, the diatonic chords function exactly the same as the major key.
What's worth pointing out is that the natural minor scale contains a m7 instead of a M7, which weakens the tension created by the dominant-function chords and thus weakens the dominant - tonic resolution.
Sample Progression
Am Dm/A Em Am i iv v i E--0------1------0------0-- B--1------3------0------1-- G--2------2------0------2-- D--2------0------2------2-- A--0------0------2------0-- E----------------0---------
Here's the archetypal tonic - subdominant - dominant - tonic progression.
And let's redo our bigger progression from C Major, except using the minor tonality:
Am C F Bdim C F B° Em Am i III VI ii III VI ii° v i E-0-------------|-0---1---1------|-0---1---1----0-|-0---------- B-1-------------|-1---1---3------|-1---1---3----0-|-1---------- G-2-------------|-0---2---x------|-0---2---x----0-|-2---------- D-2-------------|-2---3---3------|-2---3---3----2-|-2---------- A-0-------------|-3-------2------|-3-------2----2-|-0---------- E---------------|----------------|--------------0-|------------