Circle of fifths - 24 keys in music

Introduction to Keys in Music

This is about the keys in music. People often say that word when they talk about music, but what does that mean exactly?

First of all, why do you need keys in music? Can’t you just go ahead and start singing or playing guitar without referring to such obscurity? Well, yes you can, and indeed we do most of the time. When we hum in the shower, we’re not thinking about keys, we’re just singing a tune.

But then, that “tune”, most of the time, is in a certain key. What that means is that your melody is made of a selected set of musical pitches. There are 12 pitches in an octave and they are A, A#, B, C, C#, D, D#, E, F, F#, G and G#.  And, all popularly-known song melodies deliberately skip some notes out of these 12. That’s how a song manages to sound pretty, or melancholic, or however it’s meant to sound.

Take the melody of Love Me Tender, for example. Yes, the famous Elvis Presley song. I sang this with Pakistani 1st graders in class. I think I’m the only guy who’s done that. Anyway, I’ll start with A and spell out the beginning of the melody. It goes like this:

A – D – C# – D – E – B – E

Notice it’s picking up the A and B and C# but not A# or C? Likewise, it’s using D and E, but not D#. That’s what keys are all about. It’s about selection. This melody, by the way, is in the key of D Major. How do I know it? Because I know the rest of the song. I know the entire melody, and I know the chords played beneath it. That’s more than enough to tell which key it belongs to.

The song goes on and reaches the so-called Chorus part (the catchiest part of the song). And there, it picks up some more notes like F# and G. So if I collect all the notes and list them in an alphabetical order, it’ll be:

A – B – C# – D – E – F# – G

These seven notes constitute the D Major Scale. Why do I call it D Major instead of A something? First of all, the song melody ends with D. The last note of it is D. And you’re supposed to use the last note when you determine the key of a song. I don’t know why. You’re just supposed to. Well, it kinda makes sense because the last note does sound important and feels like it defines the music. So, by music theory and by natural feeling, I’m bound to say that this song is in the key of D something.

And then, you look at the other notes. I’ll list the notes again, this time with D at the beginning:

D – E – F# – G – A – B – C#

Now, in popular music (by which I basically mean any music commonly known to people world wide), it’s either a major scale or a minor scale that’s used for the melody. So in this case, our choice is narrowed down to D Major scale and D Minor scale.

(In addition to Major and Minor, there are some other possibilities such as Mixolydian or Phrygian Dominant especially when you hear the music from India or the Middle East. And Greensleeves, the famous English song from the 16th century, uses Dorian, which is kind of like a major-ish minor scale. More on these in another post.)

Okay, so we can get paranoid and keep worrying about some uncommon scales, but we’ll take the short cut and assume it’s probably either D Major or D Minor. It’s a safe bet. Then look at the 3rd note. The F#. That’s what we call a major 3rd, which means it’s 4 semitones above the 1st note. This is pretty much enough to tell it’s D Major here. If it’s D Minor, the 3rd note has to be F, a minor 3rd.

So that’s roughly how you find which scale is used for the melody of the song. But what about the key? Isn’t this post supposed to be about keys? Why am I writing so much about scales? That’s because you need to know the scale being used in order to tell a key. In this example, it’s the D major scale that’s used, therefore the song is in the key of D major, or key of D in short.

A few interesting facts about keys in music:

Keys can change. You can go from one key to another in the same song. Even in popular music.

Ask Stevie Wonder if you doubt it. Or listen to You Are The Sunshine Of My Life and notice the mood changes from cheerful to sad in some parts of the song. That’s because the key has changed from major to minor.

There are 24 keys in music, but it’s also correct to say there are only 12.

That’s because every major key is paired to a so-called relative minorkey. Look at the image again (which I have so proudly created today). Notice how the key of Am is placed right under the key of C? They are relative. So are G and Em. D and Bm. And so on. Relative keys use the same seven notes. More on relative keys in another post.

Okay, that’s it for today. I’ll post more on some related topics like modes and key changes (transposition). Thanks for reading. Good night.