The dominant chord in a minor key...

Hey everyone

I have read from a few websites/books that it is a good idea to turn the "Vm" chord into a "V7" chord when you are working in a minor key, so that it points more strongly to the "I" chord. But wouldn't you then be out of key by changing the minor 3rd in the "V" chord into a major 3rd? I don't understand how this works as you would also have to change that note in the melody to avoid sound dissonant, or is that the whole idea? I was thinking maybe you should make that a permanent change for the key?

So for example if you are writing in A minor, change the G to a G♯ and keep it that way for both the harmony and the melody?

How does this whole idea work?

Thanks for your help

You can use both forms - V/v - it depends entirely on the situation. But remember V is the true "dominant chord" in any piece in a major or minor key - you can't have a perfect cadence in the tonic using v - I.

Getting back to your example, I think the basic guideline is that in A minor, G natural leads down to F natural. G# usually leads up to A (which is why we have the melodic minor scales ascending and descending).

I hope that helps...

The minor keys come from the old Aeolian church mode (A to A, diatonically - i.e., all the white keys). When they wrote melodies in the church modes, they soon realized that having the interval between the 7th and 8th notes as a semitone creates a much stronger cadence, as in the Ionian mode (which is what turned into the major keys); so, if the mode didn't already have that feature, or if it had a semitone above the 1st note as part of the mode (Phrygian and Locrian - E to E and B to B, respecitively) then they added the raised 7th at cadences, if it fit with the harmony. The reason they didn't do it in Phrygian and Locrian is because of the odd relationship between the raised 7th and the 2nd (9th) notes (D# and F, in Phrygian, A# and C in Locrian); this is why we also raise the 6th when moving to the raised 7th in minor, the augmented second that would result from the normal 6th with the raised 7th was undesirable, for whatever reason.

Eventually, this became a system of 'raise the 6th and 7th notes when moving up the scale towards the tonic' and 'leave them be when coming down, or when not reaching the tonic'.

That's why you raise the third in the V chord in minor, to create a stronger cadence with the raised 7th, but why it's not part of the key signature. It applies to both melody and harmony (but the raised 6th applies typically to melody only).

This video is a neat demonstration of what Wayne is talking about. The video compares notes in a mode/scale to rungs on a ladder, and calls it a "variable rung". (edit: He then goes on to draw a comparison with Blues, which has a "bendy rung").

(this is part 2 of a longer series, and you'll have to click through to part 3 to get the example of a "horrendous pileup" and the section about Blues.)

Thanks for the replies everyone

Ok so I have been looking into the Melodic minor scale and it looks very interesting, just a few things I don't quite understand in it's execution.

I understand the difference ascending and descending but I don't fully understand why it turns back into natural minor going down.

Let's say the V7 chord is being held for a while and I wanted a descending melody with it. I would descend in natural minor, but then two of the notes would clash with the major 3rd in the V7 chord.

So if I was in Am, A and G in the melody would clash with G#. Why wouldn't you also descend in melodic minor so the notes match the chords? I know you go back to natural minor to preserve the minor sound, but then the notes melody are different from the chord and you get an unwanted dissonant sound.

I'm probably asking a stupid question but I would like to fully understand the application for this scale and I'm just a little lost with the clashing notes when descending.

Thanks for your time

It simply turns into the natural minor going down because it's the natural form of the scale, and doesn't need to be altered for the cadence. It's not that it 'turns back', it just doesn't become altered. It doesn't need to be. If it does, as in your example, you alter it.

Incidentally, the Tudors did use those clashes (I think), but they're not common in common practise music.

I wouldn't get too hung up on the ascending vs descending thing. It's not like you can only sharpen the notes when the melody is going upward and only flatten them when it's going downward. From a voice leading perspective, it's true that sharpening gives the line an upward tendency, and flattening a downward tendency. But from a harmonic standpoint, which notes you pick will be dependent on the underlying chord, and unless you specifically wanted that clash, you'd just pick one or the other.

Remember that, for example, in the key of A minor, you also have a C chord (III) and a G chord (VII) and these both depend on using the G natural.

This is why I like to think of them as "variable rungs" depending on the harmonic context, you can pick whichever one fits. Normally, you'd pick the natural minor scale version, *unless* you need the G# to create the strong V chord (which is a pretty common exception).

I like to think of the 6th scale degree (F, in A minor) as getting "pulled along" by the 7th degree, because if the 6th degree stayed flat while the 7th degree sharpened, you'd have an awkward augmented 2nd. So you also sharpen the 6th to avoid that whenever the 7th is sharpened (e.g. in a V chord). But the flattened 6th is required harmonically for other chords like iv (Dm) and VI (F).

Thanks everyone, I understand it now.