Key Signature

This is a preview of the educational program A Jazz Improvisation Almanac which is under development for the Outside Shore Music Online School. Feel free to browse this preview and learn what you can from it. For a more completed product, though, check out the original freely browsable jazz textbook, A Jazz Improvisation Primer.

While the chromatic scale contains all the notes used in Western harmony, most compositions are based on scales that contain only a subset of these notes. The most common such scale is the major scale. The C major scale is the scale obtained by playing, on a piano, all the white keys from one C to the next one higher:

[EXAMPLE]

The major scale is discussed in greater detail in a later chapter. You may wish to skip ahead and read the section on the major scale now if you are not familiar with the various major scales.

If the most of the phrases in a composition come from the same scale, the piece is said to be in the key of that scale. For example, here is an Eb major scale:

[EXAMPLE]

The following piece primarily uses notes from the Eb major scale, and is therefore said to be in the key of Eb major:

[EXAMPLE]

Music based on major scales other than C would tend to contain many accidentals and be difficult to read. To make things simpler, a key signature is often employed to specify up front which notes are to be altered from C major, eliminating the need for so many accidentals throughout the piece. A key signature is simply a collection of accidental signs that are placed toward the left of each staff as a reminder to the reader that all occurrences of those notes, unless otherwise specified via an accidental, should be altered.

For instance, the above piece would normally be notated as:

[EXAMPLE]

Naturals may be used to cancel the effect of the key signature for any given note:

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Key signature changes may occur within a piece of printed music:

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Each major key has its own key signature. No two are alike. The major key signatures are as follows:

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The key signatures are listed in this particular order to emphasize the patterns they form. The key of C has no flats and no sharps, but as one moves among the various keys listed above, the key signatures add sharps or add flats. The patterns are related to the circle of fifths, which is discussed further in a later chapter.

While one could create a key signature to correspond with any of the various scales discussed in this program, it is traditional to use only major scales to create key signatures. Music based on other scales is usually either written with the closest corresponding major key signature, or no key signature at all:

[EXAMPLE]

Copyright 2000 Outside Shore Music
Authored by Marc Sabatella

Key Signature