Learning to Read Music: Musical "Keys"

If you've ever been in a band, played or sang at a special event, or sung in a choir, you've probably heard your fellow musicians say something like:

"This one is played in the key of F".

What this means is that the note "F" is the natural home to which you return as you sing or play the song. This is fairly difficult to explain, but has two very practical results for the musicians.

1. The key determines the pitch range you have to work within.
2. The key tells us which notes are to be played as sharps or flats.

Let's have a brief look at these two things...

1. Pitch Range 

Imagine you're singing a solo at the Christmas concert at your school. You're going to sing the song "Joy to the World". 

You give it a try at rehearsal, but it doesn't go too well at first. You can't hit the high notes!

Your piano player says "We're doing it in the key of F. I guess that's too high for you. Let's try it in D."

You try it and it works. You can hit all the high notes and all the low notes.

What has changed?

It's actually pretty simple. Every song contains a range of notes organized around a "home" note. In the song "Joy to the World" that natural home happens to be both the first note of the song, and the last note (an octave lower).

If you try singing it in the key of F, you know that you'll have to hit both a high F and a low F. If you're not able to do that, just try moving the natural home lower.

That natural home note is also called the "root" or "tonic". The song "Joy to the World" is built around a major scale with the root (or tonic) as the first note (the lowest one) and the last note (an octave higher.) 

2. Sharps and Flats

As I've previously pointed out, songs are built on scales. And scales have a starting point that determines the pitch range used in the song.

But that isn't all. 

Without going into a lot of detail, let's just say that every major scale has the same pattern. It consists of 8 notes (if you include both the starting and ending notes), and the pitch gaps between those notes is the same from scale to scale.

This piano keyboard gives us a graphic way to look at this. If you start on C and play a series of white notes you will come to C again, eight notes higher. These white notes represent what are called "natural notes" - C-D-E-F-G-A-B-C.

But some notes in the sequence are separated by a black note, and some are not. In fact there are only two note pairs that don't have a black note between them: E-F and B-C.

The notes on the piano are all a semi-tone apart. And as we can see, most of the time the notes of the C scale are two semi-tones - or a full tone - apart. 

But in two cases they are only one semi-tone apart.

That gives us a major scale pattern with the sequence of tones (or "steps") and semi-tones (or "half steps") changing as the anchor point of the scale changes.

If the anchor point is C we will play (or sing) one set of notes, centered around C. But if we move the anchor point up to D or E or G, the song will be centered at a different point and, as a result, the set of actual notes we sing or play will be different.

And here's where sharps and flats come in: the gaps between the notes will be the same, but because of the irregularity of the whole-step/half-step pattern, the non-natural notes (sharps or flats) will fall in different places.

Just to take a fairly simple example, the song "Ode to Joy" starts out: (where the number is the note of the major scale): 3-3-4-5-5-4-3-2. In the key of C this would be E-E-F-G-G-F-E-D, but in the key of D it would be F#-F#-G-A-A-G-F#-E.

How the musical staff helps simplify this

As we said at the beginning, changing the key of a song has these two important effects for the singer or instrumentalist.

First, it pushes the range of musical tones in the song either up or down.

And second, we end up playing some notes as sharps and flats, because the gaps between notes fall in different places.

For the singer this second point is not significant. But for the guitarist, pianist, or trumpeter, etc. it is very important. Because now it means some notes have to be played as sharps or flats; and the song sounds terrible if you screw that up.

What the musical staff allows us to do is to indicate that we are playing in a "key" where certain notes are to be played sharp or flat all the time (unless otherwise indicated).

The use of the staff allows us to put the complicated musical theory aside and just focus on playing the correct notes.

*To keep it simple, C# and Db are the same note - the note between C and D. When we're thinking in terms of sharps - e.g., in the key of D - we think of this note as C#. But when we're thinking in terms of flats - e.g., in the key of Gb - we think of this note as Db. 

Check out more articles on music theory for guitar.