Scale degree in minor key

Question

I am just beginning my ear training and I have a question about hearing minor scales.

Music theory tells me that minor scale degrees work similarly to major scale degrees. For example in the key of Am the subdominant chord would be Dm and the dominant chord would be Em (or E).

But quite often I stumble upon songs that tend to use the degrees of the relative major key. For example, a song in Am would not use Dm or Em at all, but instead have some F and G chords that seem to function as subdominant and dominant (like they would in C, the relative major key)

Is such a song really more of a major song that uses its relative minor as a replacement for the tonic? Or what is going on here?

Answer 1

Subdominant and dominant are tonal music terms, they may or may not make sense in a modal context. In tonal music (like common practice era classical music) you are hard pressed to find an Em functioning as dominant for Am. E is used almost exclusively.

Today's popular music has more modal roots. A (non-raised) seventh degree major chord (G in Am) is a very popular way to connect to the tonic. I'm not sure whether labeling it as a dominant is 100% correct though; it doesn't have the strong tendency for resolution that E or E7 has. The lack of this strong tendency for resolution is what distinguishes aeolic (modal) minor from tonal (melodic/harmonic) minor.

F is the relative major of subdominant Dm. It's used quite often as a subdominant substitute in tonal music too. F -> E -> Am is a common cadence. F7 -> E7 -> Am (actually it's not F7, it's an augmented sixth chord) is even more common. So there's nothing surprising for it to be used for a similar function in popular music.

Answer 2

Maybe it comes down to the Human predilection to label everything. In, say, Cmaj., all the white notes( aka keys) on a keyboard can be used; n Amin., the same. They're the diatonic notes. So if a melody is only using those white notes, any chords produced from their combinations will fit the melody at some point. When the melody seems to gravitate more towards the C, we like to say it's IN C, and vice versa. Sometimes fortified by the use of the raised leading tone, G#.

In Cmaj, there are 3 minor harmonies which are commonplace, and in Amin there are 3 major harmonies. So moving from one to another is very natural.A mild modulation may be construed if a tune in Cmaj has a few bars consecutively in using Am, Dm and Em, but has the key actually changed?

Look at 'Fly Me to the Moon. It starts on Am, but ends up on Cmaj. So which key is it in? It uses most of the chords from both keys, so to speak, so it could be argued that it's in Amin because there's a dominant E to get there, or it's in Cmaj because it finishes on that chord.

And that's all before we start considering the parallel minor...

Answer 3

There are three basic functions a chord can have in a song: Tonic Function, Subdominant function, or Dominant Function. They get their functions from their numerical position in a key.

1. Tonic Function (stability) I, III, VI
2. Subdominant Function (contrast) II, IV
3. Dominant Function (tension) V, VII

This works in Major or Minor, A III chord and a bIII chord are both tonic function chords. In Rock and Blues I, IV, V are the three most important, in Jazz I, II, and V are.

The bVII chord (G or G7 in A minor) does create tension that can be resoved by whole-step to the tonic, but its not as strong as V to I.

The bVI chord (the F in A minor) is normally a Tonic function chord, however you are correct it can take on the Subdominant function, usually when moving to the V (E). The easiest way to wrap your head around it is to think of it as a tritone substitution for the Subdominant II chord.

Given a basic progression you can create some variation in the chord progression for swapping out a chord that has the same function. The reason this works is because they share many of the same notes, and this process is often called Common Tone Substitution for that reason.

It is common in minor harmony to change the qualities of the chords as well. The normally minor V- chord is almost always changed to a dominant V7 or major to create stronger resolution to the I-. It is also common to change all the chords except the root chord to Major chords. House of the Rising Sun is a good example. You can also change all the chords to Major chords, from the perspective of popular music, it remains minor as long as the roots of the chords in the song, together add up to a minor scale. This is how rock and metal songs played only with power chords manage to be Major or Minor.

Here it is laid out in a table on my website:

Chord Functions and the Uppercase Roman Numeral System