Strict Diatonic Harmony in Minor Keys - is it even a thing?

Question

I realize that minor keys normally add non-diatonic tones, particularly from the harmonic minor scale.

Ruling that out, if we stick to the actual diatonic notes of the natural minor scale, and the seven triads based on them...

1. Is strict diatonic harmony EVER used in minor keys? Every question I can find about minor keys is answered with something about the harmonic minor scale, or substituting the major V as a dominant.

2. Do any of the 7 diatonic triads perform a Dominant function? (Actually, this answer seems to say that NONE of the diatonic chords perform a dominant function, and thus a minor key MUST use non-diatonic tones.)

3. Is there any diatonic chord that is 'normally' played as a seventh chord in minor keys? (Like the V chord is usually played not as a triad, but as a seventh chord, in major keys.)

Sorry this is 3 (or 4) questions instead of 1, but they are tangled up in my mind and I'm not sure how to separate them. Maybe there is one answer... maybe strict diatonic harmony is just never used in minor keys.

Answer 1

Music that strictly adheres to the diatonic natural minor scale would be considered modal. That is, what we typically think of as music in major or minor keys — "tonal" music — uses alterations of the natural minor scale; "modal" music specifically avoids those alterations. When used in a modal context, we refer to the scale/key as aeolian.

Is strict diatonic harmony EVER used in minor keys? Every question I can find about minor keys is answered with something about the harmonic minor scale, or substituting the major V as a dominant.

Wikipedia offers four examples of songs written in the aeolian mode (i.e., using the natural minor scale exclusively):

• Bob Dylan – "All Along the Watchtower"
• R.E.M. – "Losing My Religion"
• Phil Collins - "In the Air Tonight"
• Alter Bridge - "Blackbird"

Do any of the 7 diatonic triads perform a Dominant function?

This depends on how strictly "dominant function" is defined. The iio, v, and VII chords can all have a (weakly) dominant function. The VII chord, in particular, is sometimes referred to as the "backdoor" dominant.

Is there any diatonic chord that is 'normally' played as a seventh chord in minor keys?

In jazz, all of the diatonic seventh chords are reasonably common, especially iimin7b5. In popular music VII7 is fairly common.

Answer 2

Yes, you can find music that would just stick to the key signature, all natural minor if you want to name a scale.

You would refer to such music as "modal."

When the minor mode music uses proper dominant harmony with a raised seventh scale degree for a leading tone that is truly being "in a minor key."

...Every question I can find about minor keys is answered with something about the harmonic minor scale, or substituting the major V as a dominant.

I think the simplest way to think of it is just raising the seventh scale degree to get a proper leading tone. There is no switching of scales or substitution of chords. The key signature isn't a scale, and being in a minor key isn't a scale.

Do any of the 7 diatonic triads perform a Dominant function?

Dominant of what? The dominant of tonic i will require a raised seventh degree, but the VII chord without any chromatic alteration is the dominant of III. That's something to be aware of, because depending on how the VII to III relationship is handled the tonal center could drift from i to III and that would redefine what is the dominant.

Is there any diatonic chord that is 'normally' played as a seventh chord in minor keys?

In common practice, classical style, by far V and ii, and viio are the chords that take sevenths in both major and minor keys. But even in that style all the chords can take sevenths. You just wouldn't have cadential harmony to the tonic with a seventh. The tonic chord is normally a plain triad.

When you switch over to modal harmony you need to get more specific about what you're doing. There is Renaissance style modal and various modern styles like folk and jazz. Let's skip the Renaissance stuff, in modern modal styles you could have sevenths on any chord.