Theory 101: Pt 6, Keys

We’ve been working mostly in the key of Cmajor for most examples. Music is written in different keys, representing each of the 12 pitches. Each key has a particular set of

pitches that correspond to it. We call this a key signature, as it is a shortcut to figuring out the intervals to construct a major scale on a given Tonic. There are Sharp keys and l0. Flat keys, typically they are not mixed but there are exceptions.
Sharps occur in the following order: F# C# G# D# A# E# B#
Flats occur in the reverse: Bb Eb Ab Db Gb Cb Fb
The order is always adhered to, for example a key with 3 flats has Bb Eb and Ab. Assuming the major mode:
C has no sharps or flats
G has 1 sharp
D 2 sharps
A 3 sharps
E 4 sharps
B 5 sharps
F 1 flat
Bb 2 flats
Eb 3 flats
Ab 4 flats
Db 5 flats

Other modes including minor can be derived from the major signature, so it is usually sufficient to memorize it alone. Later we’ll look at the circle of fifths which will greatly simplify this process.

Typically, music is not written with more that 5 sharps or flats, as an enharmonic key usually offers a better alternative, but it does happen from time to time.

Confused? Well, this can be a lot to take in, fortunately there’s a handy device that works like an answer key for most scale/chord questions.

The circle of fifths/fourths:

A handy device that decodes scales and chord progressions that should be memorized fully.
In fifths (sharps)
F-C-G-D-A-E-B-F#-C#-G#-D#-A#-E#-B#

In fourths (flats) E-A-D-G-C-F-Bb-Eb-Ab-Db-Gb-Cb-Fb