Music Theory for Songwriters

The main idea here is this: in major keys there's a strong tendency to allow the bass note to be the root of the chord (especially when first learning to write songs). But in minor keys, even when you are beginning, certain bass notes tend not to be the root. When the bass note is 2, 3, 6, or 7, quite often that bass note is the third of the chord. Knowing this right from the beginning may help you as you explore progressions in minor keys.

Minor Keys - Concept #7

Each minor key is related to one of the major keys, or to put it another way, each major key has a relative minor key.

The names of the two keys, the major key and its relative minor, are always three half steps apart. For example, C major has a relative minor, A minor. Notice that the note A is three half steps down from the note C. Similarly, D major has a relative minor, B minor. The note B is three half steps down from the note D.

These two keys, the major key you've chosen and its relative minor, share the same "key signature." The key signature is the number of sharps or flats in that particular major scale, and it is written on the staff following the clef sign at the beginning of each line of music. For example, the F major scale has one flat in its key signature. So the Dm scale (the note D is three half steps below the note F) also has one flat in its key signature. In the same way, G major and Em share the same key signature (one sharp).

There are two things to notice about this. First, when you look at a piece of written music, the key signature won’t necessarily tell you which key the song is in. It might be major, or it might be in the relative minor. We’ll have to look at the notes and chords to tell which it is. (It could also be in one of the modes, but for now we'll limit our discussion to major and minor.)

Secondly, if the piece is written in minor, there will very likely be a number of "accidentals" (notes with a sharp, flat or natural sign in front of them). This is because the minor scale that uses the same key signature is what we call "natural minor," and harmonic minor (the minor scale that allows the V chord to be major) requires that we raise note 7 a half step. This raised note 7 has to be written into the music as it happens. For example, if you see one flat in the key signature, the song may be in F major, or it may be in Dm. But if it is in Dm, there's a good chance you'll see a number of C# notes in the score, because C# is the raised seven note which gives us the A major chord as the V chord.

Here is a list of the major keys and their relative minors.

C major (no sharps or flats) is related to A minor.
G major (1 sharp) is related to E minor.
D major (2 sharps) is related to B minor.
A major (3 sharps) is related to F# minor.
E major (4 sharps) is related to C# minor.
B major (5 sharps) is related to G# minor.
Gb major (6 flats) is related to Eb minor.
Db major (5 flats) is related to Bb minor.
Ab major (4 flats) is related to F minor.
Eb major (3 flats) is related to C minor.
Bb major (2 flats) is related to G minor.
F major (1 flat) is related to D minor.

The other possibilities, though rarely seen, would be...
F# major (6 sharps) is related to D# minor.
C# major (7 sharps) is related to A# minor.
Cb major (7 flats) is related to Ab minor.

This discussion of major keys and their relative minors leads us to a very important concept when writing music in minor keys.

Minor Keys - Concept #8

This is the "Switch-Over" concept. That's not its real name, but we'll call it that for the moment. The "Switch-Over" concept is this: if you are writing or playing in a minor key, there is a strong pull to switch over at some point to the relative major key. It's almost like driving a car on a highway and switching lanes. Then a little later, you might switch back to the minor key where you started. Once you get used to this, it happens quite easily.

You might ask, “If this happens in minor keys, does it also happen when writing in major keys? Do we switch over to the relative minor and back?” The answer is you could if you wanted to, but it doesn't seem to happen nearly as often. For some reason, writing in minor lends itself to jumping across to the relative major and then back.

In my own mind - this is a personal explanation; other teachers might explain it differently - I compare it to the concept of gravity. Earth has a strong gravitational pull, and anything spinning around the earth, like the moon or a satellite, has a predictable orbit. But what if you traveled to a place where gravity wasn't so strong, and where more than one planet was part of the picture? You might be sort of loosely pulled in the direction of one planet, and then, when another one came near, you might orbit that one instead. To me, minor keys have the feeling of "a little less gravity," or to put it another way, a little more freedom to escape and land in a different key center.

“Switching Over” - How Does It Work?

It's very simple once you catch it. It works like this. These two keys, the minor key and its relative major, share the same scale notes (except for the raised 7 note in harmonic minor), which means they share some of the same chords.

Let's take the key of A minor as an example. In the progression Am - Dm - Am (i - iv - i), we played Dm as the iv chord. But Dm is the ii chord in C major, and we already know from writing songs in C major that Dm - G - C is a nice, smooth progression. Because we've played this many times before, and because A minor is closely related to C major, you might someday, while experimenting in the key of A minor, play Am - Dm - G - C. In other words, having started the progression in A minor, when you hit the Dm chord, you might switch over to a progression you know from the key of C major. By the time you reach the C chord, you realize you've "changed lanes."

What really happened was you played a chord that could be "either or.” It would be one thing in the key of A minor; it's something else in the key of C major.

In music theory, we call switching from one key center to another "Modulation." One of the ways of "modulating" is to find a chord that the two keys share. You approach the chord from one key, and leave the chord in the other key.

There are other chords that work also. The Am chord is chord i, but it's also vi in C major. Then there's the F chord. It's chord VI in A minor, but it's also IV in C major. With so many options, it's easy to step back and forth.

Here are some more to try.

Am - Dm - Am - G - C
Am - E - Am - Dm - Am/E - FM7 - G - C
Dm - Am - Dm - E - Am - F - Dm - G - C

Getting back to the key of A minor is also easy, especially if you use an E chord, or an E7 chord. The E chord has the note G# in it, which isn't part of the C major scale, so it tells the listener right away that something is happening. When you introduce the E chord or one of its variations (E7, or E7/B, or E7sus4 followed by E7, etc.), everyone can hear A minor coming back. You can also get back to A minor using shared chords like Dm and F.

What Does This Mean?

It means if you would like to write a song in a minor key, you may write it using just the chords we normally associate with harmonic minor, or you may widen your view a little, and step right off the map, landing in another key, the relative major. This adds a lot of possibilities.

Even More Possibilities

And one more thing: not only can a minor key jump to its relative major; it can also jump to its "parallel major." Jumping to the parallel major is easy. If you are playing in A minor, start playing in A major. If you are playing in C minor, start playing in C major. (If the song you are writing benefits from the sound of the parallel major, you can modulate instantly at any time, jumping back to minor when you are ready to come back.)

Let’s Review

In this section we discussed four ideas.

First, when exploring minor keys, begin with i, iv, and V. This is the sound you will want to hear clearly before going any deeper.

Second, we allowed the bass note to play each note in the harmonic minor scale, and asked which chords would likely be played for each of these bass notes. We noticed that when the bass note is note 2, 3, 6, or 7, one of the common chord options is whichever chord has that bass note as its third.

Third, we talked about modulating (or "switching over") from a minor key to its relative major and then back. We saw that this happens easily because a minor key and it's relative major share some of the same notes and chords.

Fourth, we mentioned that a minor key is quite close to its parallel major, so jumping to the parallel major and back is also an option.

Enjoy exploring, and then move on to to Part Thirteen.