Understanding minor key harmony

Question

A comment discussion under this question from me, clued me in to the fact that I don't really understand how minor keys work very well. So here is what I think I know

The natural minor comes from the Aeolian mode of the major scale. It gives us the following triads for use in harmony:

i ii° III iv v VI VII

From what I have been told, classical minor harmony also utilizes the harmonic minor. which is the same scale with a sharpened 7th. This implies the following triads (notated with respect to the degrees of the natural minor):

i ii° III+ iv V VI ♯vii°

Now the comment "the 6th and the 7th scale degrees can be modified whenever the composer feels it's necessary to do so." leads me to believe that this is not an all or nothing thing, and I can more or less mix and match to suit the sound I am looking for. First of all, am I right up to this point? Should I tend to favor the triads from the harmonic minor?

Taking this further, I could imagine different combinations of sharpening or flattening the 6th and 7th scale degrees. Well there would only be 3 other choices really: Melodic minor, a ♯6, or a ♯6 with a ♭7. These will each imply different triads. Are any of these (besides melodic minor) going to be harmonically useful? Can I effectively use any of the resulting triads in a progression and not sound out of key? I realize this may be subjective to a certain degree.

To throw another wrench into the gears, how do other "minor" modes play into this? I am considering a scale mode to be "minor" if its 3rd is a minor third and the 5th is a perfect fifth. For example, in the dorian mode: Can I play the same tricks with the 6th and 7th there too? Or will I run into problems?

Answer 1

This is an excellent and important question. In a minor key, all 4 possible combinations of 6th and 7th scale degree are used, and each combination corresponds to a scale:

• b6, b7: natural minor (aeolian)
• b6, 7: harmonic minor (creates a dominant V chord with a leading tone to the root of the key, so it was 'invented' for harmonic reasons)
• 6, 7: melodic minor (removes the augmented second interval between b6 and 7 of harmonic minor, so it was 'invented' for melodic reasons)
• 6, b7: dorian

All chords from these three scales can be and are used in compositions in a minor key. They can (and again are) rather freely mixed by composers in one and the same piece. It is a big misunderstanding by beginners that pieces are written 'in melodic minor' or in 'harmonic minor'. Usually a piece is just in minor and all combinations of 6th and 7th scale degrees are used harmonically and melodically.

The truth of my quote "the 6th and the 7th scale degrees can be modified whenever the composer feels it's necessary to do so" was doubted in another answer. However, it is almost a tautology because there are no rules and if there were any, composers would (and should) not care about them. Of course, certain combinations occur more often than others, but all are allowed and all are used, no matter if you analyze Bach or modern jazz pieces.

As for modes, in a purely modal piece (e.g. in dorian) you are not as free as in a general minor key. But this is the composer's choice because he/she decided to write a modal piece. However, all other notes can always be used as passing notes or approach notes. Here it's mainly the rhythmic placement that determines whether a passing or approach note sounds good. The notes of the mode are usually placed on stressed beats, whereas all others are usually placed on unstressed beats.

EDIT:

Inspired by a comment (see below) I'd like to give one famous example of the fact that in a minor key the major 6th, major 7th, minor 6th and minor 7th can appear in any possible combination, and that composers usually don't care much about academic guidelines (like using major 6th and major 7th ascending, and using minor 6th and minor 7th only descending, etc.). The following example is by J.S. Bach. Note the descending sequence of root, major 7th, major 6th and fifth in the last bar. And we're not even talking about 20th or 21st century music yet!

(from The Chord Scale Theory & Jazz Harmony by B. Nettles and R. Graf / Berklee College of Music)

Answer 2

Here's a simple way to summarize Western Minor harmony.

Leaving aside exotic variants, most Western sections in the minor key are constructed from 2 scales and 2 major key modes in varying combinations.

Lets deal first with the modes:

Consider C Major. The basic baby chord set is:

-------- C Dm Em F G Am and Bo.
figures: I ii iii IV V vi vii o.

The AEOLIAN Mode of C major Starts on A. I'm going to call this A Aeolian. (But some people call it C Aeolian. Let's not go there today.)

Note that "A Aeolian" and "A Natural Minor" refer to EXACTLY THE SAME THING.

The basic baby chord set is THE SAME but stars on A:

-------- Am Bo C Dm Em F G.
figures: vi Vii o I ii iii IV V

(Notice I didn't CHANGE the figures, cos' that WILL drive you crazy.)

Am is the MODAL TONIC. G is the MODAL DOMINANT.

(G, but not necessarily G7. G Sus is more common.)

God Rest Ye Merry Gentlemen is in Aeolian.

You could write a tune with just that.

Now consider G Major. The basic baby chord set is:

------- G Am Bm C D Em and F#o.
figures: I ii iii IV V vi vii o.

The DORIAN Mode of G major Starts on A. I'm going to call this A Dorian. (But some people call it G Dorian. Again, let's not go there today.)

The basic baby chord set is THE SAME but stars on A:

------- Am Bm C D Em and F# o G.
figures: ii iii IV V vi vii o I .

Am is once again the MODAL TONIC. G is once again the MODAL DOMINANT.

Scarboro Fair is Dorian.

You could write a tune which combines the chords in these 2 modes.

In order to get back to the modal tonic Am you would most likely use the G modal dominant. (Same in both cases).

And that's exactly what everyone did in the middle ages.

Then along came the Germans.

The Germans stole an arabic scale from the Spanish and adapted it. Its called the Harmonic Minor:

------- Am Bo C+ Dm E (E7) F and G#o.
figures: i ii o III+ iv V VI vii o .

That fact that the DOMINANT is a nice fat juicy tense E7 gives tunes a more dramtic climax

E7 -> Am

than the older

G -> Am resolution.

Now you have three keys with which to weave your progression.

The other Key is A Melodic Minor. (There is rather a lot of controversy and confusion surrounding this that deserves a separate post.)

------- Am Bm C+ D E (E7) F#o and G#o.
figures: i ii III+ iv V vi o vii o .

Now we have four sets of chords to work with. Very often writers modulate freely between them.

Aeolian ------ Am Bo C Dm Em F G.
Harmonic ------ Am Bo C+ Dm E (E7) F G#o.
Dorian ------ Am Bm C D Em F#o G.
Melodic ----- Am Bm C+ D E (E7) F#o G#o.

A realy good example is Greensleeves.

It turns out that you will frequently find out that:

-- a section starting out in Aeolian will become Harmonic at the climax --
-- a section starting out in Dorian will become Melodic at the climax --

This is because there is only one note difference between them.

One last point. At any one time the key or mode will be purely Dorian, or purely Melodic, or purely Aeolian or purely Harmonic. You won't ever see for example F AND F# in the same chord or G AND G#. You can combine these musical structures horizontally but not vertically. (Well you can do what you like, but good luck with your audience!)

See @Matt L 's wonderful Bach example in this post.

Answer 3

There are two ways at to look at this question from a classical music theory perspective and modern perspective.

In classical music theory, if you are in any minor key you would use the following chords:

i iio III iv V VI viio

The viio comes from the leading tone chord found in harmonic minor. You would not want to use the subtonic chord (VII) because it is V of the relative major.

In the melody you would use the melodic minor scale when going towards the tonic chord (i) and the natural minor scale when moving away from the tonic chord.

From a modern perspective it is whatever you want and what sounds good to you. You can use v or V and VII or viio and III or III+ any combination if you want as long as it sounds good to you.

Answer 4

the 6th and the 7th scale degrees can be modified whenever the composer feels it's necessary to do so.

This is not true. If the 6th is raised, then it should typically move on the the raised 7th, and that should resolve to the tonic. These degrees would typically occur as non-chord tones, most typically as passing tones. This could happen for instance against the tonic chord.

The natural 6th and 7th degrees can be used more freely. Melodically they could also appear as passing tones in a line descending from the tonic to the fifth.

However, what you will almost never see, is a descending line starting from the tonic to the 7th, that then descends to the raised 6th; not even if that raised 6th ascends again to the raised 7th.

What might occur, but not very often is an immediate juxtaposition of the descending line on the natural 7th, 6th and then fifth and the ascending line using the raised 6th, raised 7th to the tonic. The reverse though, does occur quite often: ascending line from fifth to raised 6th, raised 7th, tonic, which then immediately descends to natural 7th, natural 6th and then fifth.

"To throw another wrench into the gears, how do other "minor" modes play into this? I am considering a scale mode to be "minor" if its 3rd is a minor third and the 5th is a perfect fifth. For example, in the dorian mode: Can I play the same tricks with the 6th and 7th there too? Or will I run into problems?"

I'd say that yes, any scale with a minor third will sound as some variation of the minor scale. You can raise the 7th in dorian mode too, and whereas the dorian mode has a major sixth normally, you can use a minor sixth too. Obviously if you do that all the time, it will cease to be dorian and sound like melodic minor.

Answer 5

I spend my morning hour analyzing Bach chorales. He doesn't stay in one key very long and uses pivot chords and such. I was taught in Theory classes he did __ and didn't __ but now I'm not so convinced of these rules. I see J.S. Bach using VII and vii as well as other chords such as VI7! A good example is BWV 245.37 Christus, der uns selling macht of his Saint John's Passion. I believe what chord you are using depends on where it is going, its resolution. I have found that by listening to an analyzed Bach chorale it may sound differently than its chords are spelled. In short, brake the rules especially with good reason; what effect are you trying to make? Parallel 5ths will stand out. But maybe you want that. If you did then it is something to do. All that said, I was taught to stay away from VII and vii because they were really V7 and v7 without the root. However I don't hear J.S. Bach doing that. C.P.E. Bach, son and one of the best student's of J.S. Bach was more conservative in his use of VII and vii.

Answer 6

From what I have been told, classical minor harmony also utilizes the harmonic minor.

Maybe, maybe not. That yields a +III on the mediant which isn't a basic chord in classical harmony.

I think the Rule of the Octave is a better way - certainly a historically informed way - to understand the basic classical approach to minor harmony. The rule presents a scale in the bass and shows the standard way it should be harmonized. The direction of the bass is essential to the harmony options used. An excellent, concise overview of the rule is available from the theorist Gjerdingen. Two examples rules in minor from classical masters Fenaroli and Furno are below...

Fenaroli

Furno

During the time period of these masters roman numeral analysis didn't exist. Instead they used figured bass. If the chords used for the rule are translated to roman numerals (without inversion symbols) we get the follow list...

i
ii°
III not used, typically will be I in the relative major
iv
IV
v (minor quality, not used in cadences)
V (true dominant with raised ^7 scale degree - the leading tone)
VI not used, would be IV of relative major, raised ^6 scale degree is harmonized as `iv6`
vii° this doesn't really appear in the rule, but would be an incomplete dominant V7
VII not used, the subtonic triad, would be V in the relative major

This is how harmony was taught and understood during the classical period.

The rules seek to use only fundamental harmonies of tonic, dominant, and subdominant while eschewing secondary harmonies like the mediant, submediant, subtonic, etc.

The rule doesn't mean other chords cannot be used or cannot be found in scores. It's simply a concise way to understand harmony fundamentals in the classical style.

Also, take care to distinguish between actual chords versus non-chord tone movements. Some may say you can get a augmented +III6 in minor. But that is likely to be a root position dominant where the 5th of the chord moves up to ^3 scale degree as an escape tone. Similarly you may see things that look like 7th chords, but may be analyzed as simple triads with passing tones or other non-chord tones.

Answer 7

This is probably a rephrase of other comments but I have my own interpretation of CPP usage of minor keys. There is one minor key (the idea of natural, harmonic, and melodic minors as separate entities isn't all that important in CPP music.) The 6th and 7th step of the minor scale are mutable. Either or both may be raised and still be considered diatonic; the key isn't changed. There is a strong tendency to use the mutated notes in certain but variations are possible.

Going upward from step 5 to step 8, the 6th and 7th are normally raised; almost always with dominant harmony; usually with tonic harmony; rarely with subdominant harmony.

Going downward from step 8 to step5, the 6th and 7th are normally unraised; almost always with subdominant harmony; usually with tonic harmony; very rarely with dominant harmony.

A common seeming exception is to use the unraised 6th and raised 7th in melodies with dominant harmony as this makes steps 4,5,6,and raised 7 outline an arpeggio of a dominant 9th chord. I remember seeing this in some Mozart piano pieces.

The unraised sixth is always used as the upper neighbor to the 5th step; I've never seen a raised 6th step here (also in Major, one often uses a lowered 6th step as the upper neighbor to the 5th step for coloristic purposes.)

The augmented chord on the 3rd step is very rare (but possible in a Late Romantic style.)

A cycle of fifths (or fourths depending on how one counts) i,iv,VII,III,VI,ii0,V7,i is nice as the last three chords make an effective cadence.

So what one has is that the 7th step is raised to make the chord on the 5th step major (the minor chord can be used but it doesn't make the same kind of cadence) and the 6th step is raised along with the 7th to avoid the augmented second between the unraised 6th and the raised 7th as augmented intervals are considered difficult to sing. (Perhaps the previous sentence would have been better written in German?) Instrumentally the augmented interval is not a problem so it may be used, especially to outline a dominant ninth.

Answer 8

Harmonizing melodies is not something I have a lot of experience with, but I have done it in the past, and was very pleased with my results.

I think it's very important to understand that the 'rules' of harmony and music theory are NOT rules. They are descriptions of common practice. Be willing to experiment.

This is a great question, and I was taught all of the harmonies for the melodic minor scale when I studied music theory. Any combination of raised and natural minor 6th and 7th scales are fair game. Have fun!!! :-)