The Complete Idiot''s Guide to Music Theory

Tip

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Chapter 4:
Major and Minor Keys
49
Same as This
Scale
Notes
Major Key
B minor
D Major
C minor
E-flat Major
C-sharp minor
E Major
D minor
F Major
D-sharp minor
F-sharp Major
E-flat minor
G-flat Major
E minor
G Major
F minor
A-flat Major
F-sharp minor
A Major
G minor
B-flat Major
G-sharp minor
B Major
A-flat minor
C-flat Major

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Part 1:
Tones
50
The Circle of Fifths
There’s a quick way to remember how many sharps or flats to include with each
key signature. This method is called the 
circle of fifths;
it works like this.
Starting with the key of C, for every perfect fifth you move up, you add a sharp.
So the key of G (a perfect fifth up from C) has one sharp. The key of D (a per-
fect fifth up from G) has two sharps … and so on.
The circle of fifths works in the other direction for flats. For every perfect fifth
you move down from C, you add a flat. So the key of F (a perfect fifth down
from C) has one flat. The key of B-flat (a perfect fifth down from F) has two
flats … and so on.
The following drawing shows how all the major keys relate in the circle of
fifths. When you move clockwise around the circle, you’re moving up through
the fifths (and the sharp keys); when you move counterclockwise, you’re mov-
ing down through the fifths (and the flat keys).
All the major keys are a fifth apart in the circle of fifths.
The next figure shows the circle of fifths for the 15 
minor
keys. It works just the
same as the major-key circle; move clockwise for the sharp keys, and counter-
clockwise for the flat keys.
The circle of fifths works for minor keys, too.

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Chapter 4:
Major and Minor Keys
Accidents Will Happen
When you assign a key signature to a piece of music, it’s assumed that all the
following notes will correspond to that particular key. How, then, do you indi-
cate notes that fall outside that key?
First, it should be noted that you 
can
play outside a key. For example, it’s okay
to play the occasional B natural when you’re in the key of F, which normally has
a B-flat. No one will arrest you for it—in fact, certain types of music regularly
employ nonscale notes.
When you decide to write a note that isn’t within the current key, you have to
manually indicate the change in the music—by using sharp, flat, or natural
signs. When musicians see the inserted sharp, flat, or natural, they know to play
the note as written, rather than as indicated by the music’s key signature.
These “outside the key” notes are called 
accidentals
or 
chromatic notes;
they’re
quite common.
For example, let’s say a piece of music is in the key of F, which has only one flat
(B-flat). You want your melody to include an E-flat, which isn’t in the key. So
when you get to that note, you insert a flat sign before the E to indicate an 
E-flat. It’s as simple as that.
51
Jazz and blues music often
add flatted thirds and sev-
enths within the desig-
nated major key, which
give these styles their
unique sound.
Note
Use accidentals to indicate notes outside the current key signature.
The same theory would apply if you want to include a B natural in the same
piece, instead of the expected B-flat. If you simply insert a natural sign before
the B, you’ve accomplished your mission.
When you change a note with an accidental, that accidental applies until the
end of the current measure. At the start of the next measure, it’s assumed that all
notes revert to what they should be, given the current key. So if you flat an E in
measure one of an F Major melody, the first E you write in measure two will be
assumed to be natural; not flatted.
The one exception to this rule occurs when you tie a note from the end of one
measure to the beginning of the next. The accidental carries over—thanks to the
tie—to that first note in the second measure, as you can see in the following exam-
ple. (Ties are explained in Chapter 5.) Note that the accidental doesn’t apply to
any subsequent notes in the second measure; it applies only to the tied note.
An accidental
applies only from that
point in the measure to the
end of the measure. It
doesn’t affect those notes
in the measure before the
accidental appears.
Warning
Accidentals apply to all notes tied over a measure.

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