Functional harmony in minor

What are the ‘rules’?

Harmonic function in major is really straightforward to understand. The VII chord does not have the leading tone so is it a good cadence chord? What about the ii°? I like to use that as a cadence chord back to i but I’ve never seen it refered to. Why? I think it works just as well as vii° to I.

Also as far as Tonic - Subdominant - Dominant how does that work in minor. Is i-iv-v the same as i_IV-V? How?

What about secondary chords in minor? Any rules there?

Thanks much

That’s the thing about functional harmony; because it’s so closely tied to the major scale (and especially its historical use in European classical music), it sort of starts to fall apart the further you drift away from it. That said, it still kind of works in minor, but the “rules” are both different and less clearly defined.

Starting with the ii° chord, if anything it actually works better in minor than in major (at least imo): because the tonic is a darker sound, resolving to it from a diminished chord isn’t quite as jarring. Extending the ii° to a 7th chord gives you ii7b5, whose first inversion is iv6, which also resolves pretty well to i.

I bring this up because the standard iv and v chords in minor are in a sense, reversed from their major counterparts. The v chord doesn’t resolve to i nearly as well as in major because its third (i.e. the 7th degree of the scale) is a whole step away from the i chord’s root (rather than a half step away as in major’s V-I), so it presents a dark, almost melancholy feel (functionally, it would act as a subdominant chord). However, the iv’s third (the scale’s 6th degree) is a half step away from the i chord’s fifth, so it sort of acts as a minor leading tone, in a sense making it a dominant chord. Kind of.

If you were to use major IV and V in minor, you would be borrowing them from other scales: IV is used in dorian, which is like minor but uses a natural 6 instead of a b6 for a more relaxed sound, while V is borrowed from major, or more often harmonic minor, which is minor with a natural 7 to reclaim major’s leading tone (although this results in an unusually wide gap between the 6th and 7th degrees; this isn’t necessarily a problem, but just something to keep in mind).

Going back to functional harmony, most chords besides the i and borrowed V can act as subdominant chords. VII can be subdominant or dominant (since you’re basically using the V from the relative major), while VI can be tonic (since it’s a third away from i and thus only differs from it by one note) or subdominant (again, by serving as the relative major’s IV). Even the minor iv can act as a subdominant.

The III is basically just tonic, but because it’s also the root of the relative major scale, you have to be careful: if you sit on the III for too long, it will just sound like you’re playing in major. It’s best used in short bursts (unless you’re intentionally trying to be ambiguous, which is absolutely a valid option).

In terms of other secondary chords, you’re certainly welcome to use secondary dominants, serving more or less the same purpose they would in major (or any key, really). Sometimes you’ll see the bII borrowed from phrygian, especially in its first inversion (N6) as a subdominant leadup to V.

Hope that helps!

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Hi b2jammer

That was a really well thought out and composed reply. Very much appreciate the time you put into that. Interesting about the iv and v having opposite roles than IV and V, I will have to explore that next practice session.

I use a V (or even a V7) in a minor key all the time. I really like that sound and the juxtaposition of borrowed chords in general.

So in a minor key the ii° and iv would (could) act as the dominant (as well as a borrowed V7)? I’ll have to get on TheoryTab to see how minor keys resolve back to i regularly. But lots of really interesting ideas above for me to digest.

Regarding secondary chords, I assume still using dominant versions of said chords regardless of the chord/quality they are resolving to? I don’t think i’ve ever tried that in a minor key. I’m excited to explore that too next practice session.

Finally, and I hate to ask more of your time as you’ve been generous enough already, but (on a slightly tangential topic) how do mediants work in minor versus major keys. Mediants in general is a subject I’ve read a little on but still don’t fully grasp.

Cheers again!!

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Happy to help! Music theory is always interesting to think and talk about.

Yes, secondary dominants would be played as dominant 7ths (or major triads). As such, you’ll be leaving the key (at least temporarily), so keep that in mind when you’re writing a melody over them.

Mediants are just chords whose roots are some kind of third apart, regardless of key. Your diatonic mediants (i.e. iii and vi in major, or bIII and bVI in minor) only differ from their respective tonic chords by one note, so they sound really similar. As such, they tend to serve as tonic function chords themselves.

(There is some historical debate that major’s iii in particular is actually dominant, but that’s a whole other can of worms: 12tone has a video that goes into more depth)

You can also use chromatic mediants instead (bIII, bVI, III and VI in major; or biii, bvi, iii, and vi in minor). They differ from their I chord by two notes, so the shift between them is much more drastic; and unlike the diatonic mediants, they don’t appear in the scale. You don’t really see these in functional progressions, but they can be interesting to play around with (if I had to assign these a function, I’d say either tonic or subdominant, but that’s a judgement call. YMMV).

Then there’s the doubly chromatic mediants (biii and bvi in major, or III and VI in minor). These don’t share any notes with the tonic chord, so they sound kind of spooky and weird. You almost never see these in functional progressions either.

Cheers!

This is one of the most useful applications of the theory of “negative harmony”.

The viidim chord in a major key reflects onto the iidim chord in a minor key. They both have equal pull towards their respective tonics.

Similarly, the V7 chord in major reflects onto ivadd6. So yea, from that perspective, the iidim and iv6 chords ARE the best penultimate chord in a minor key.

New here, not sure my notation is up to snuff. Would welcome input!