Lesson 19: Keys
This lesson explains what a musical
key is. Keys are a
basic music concept which you will need in order to understand both
chord
progressions and
written music.
Before taking this lesson, you should know: major scales
(
Lesson 10: Major 1-2-3 Games).
In most songs,
one particular pitch feels like the "resting" or
"home" pitch; this pitch is the song's
key. For example, if the pitch
C feels like the home pitch, then the song is "in the key of C".
Keys can be
major or
minor. If a song's home pitch is
C
and most of the song's notes come from the
C major scale, then we say
the song is in the
key of C major. If the song's notes come from a C
minor scale, then the song is in the
key of C minor.
Now let's see how you can play the
same song in
different
keys. First, here is "Mary Had A Little Lamb" in the
key of C
major:
| Ma- | ry | had | a | lit- | tle |
lamb |
E |
D |
C |
D |
E |
E |
E |
<- Notes (click) |
| 3 | 2 | 1 | 2 | 3 | 3 | 3 |
<- Scale degrees |
Click each note button above to hear the song.
Next, below, is "Mary Had A Little Lamb" again, this time in the
key of
E♭ major:
| Ma- | ry | had | a | lit- | tle |
lamb |
G |
F |
E♭ |
F |
G |
G |
G |
<- Notes (click) |
| 3 | 2 | 1 | 2 | 3 | 3 | 3 |
<- Scale degrees |
Again,
click each note button.
Notice that when you play the song "Mary Had A Little Lamb" in a different
key,
all the pitches change, but
the scale degrees stay the
same. You can play "Mary" in
any key by playing scale degrees
3-2-1-2-3-3-3 from
that key's major scale.
Identifying a Song's Key
So, how do you
tell what key a song is in (especially if it's your
own song, or "fragment")?
Well, there's no "law" that says a song is "in a key" at all. A song (or
fragment) is only "in a key" if it gives the listener enough
musical
clues for them to feel a
home pitch.
Here are the
common clues that make a song sound like it's in a key.
Imagine a song that does these things:
-
Most 4-measure phrases start and/or end on a C major (or C minor)
chord.
-
The chord sequences in the song tend to follow the standard
tonic -> subdominant -> dominant sequence of diatonic
functions in the key of C
(Lesson 26: Diatonic Function Analysis).
-
Most of the song's notes come from the C major (or C minor)
scale.
-
The melody emphasizes the note C at important points.
If all of the above are true, then the song will probably sound like it's in
the
key of C (C major or C minor). You can take away or "weaken" some
of the "rules" above and the song can still sound like it's in the key of C;
in fact, many, maybe
most, "real" songs will break or weaken some of
these rules, because following them constantly can sound boring. But if you
remove too many of them, then the song doesn't sound like it's "in a key"
anymore.
Next:
You'll use keys to understand
chord progressions, in
Lesson 20: Roman Numeral Chords.
