Key Signatures
Warning: You must read the article “Scales” before you read this page. The topics discussed in this article are closely related to those found in the “Scales” article, and an understanding of the information in that article is crucial to the success you will have with “Key signatures.” You can find the “Scales” article on the “Theory” section of the site.
A key signature is a way to minimize writting out the accidentals of a scale. Let’s take the E major scale for example: it has four sharps; F#, C#, G# D#. If we were looking at a piece of music in the key of E major, but there was no key signature at the beginning of the music, then we would have to write down sharps (#) whenever we saw an F, C, G, or D note. Obviously, this would be a daunting, and boring, task. That is where key signatures come in.
Look closely at the E major key signature: You will notice that the sharp symbols are on the four notes that are sharped in E major: F#, C#, G#, D#.
By writting down the key signature for E major at the beginning of the piece, we would have it as a reminder for us to sharp all the F’s, C’s, G’s, and D’s of the music. In essence, the E major key signature “sharp’s for us” all of these four notes.
Order of sharps
Sharps are added on key signatures in this pattern:
F#, C#, G#, D# A#, E#, B# for both major and minor scales.
The G major key signature, which only has one sharp, would have an F# on the key signature. But an E major key signature, having four sharps, would have the F# as well as the C#, G#, and D#. Likewise, C# minor, which also has four sharps, would have the same four sharps in it’s key signature: F#, C#, G#, D#.
Order of flats
Flats are added on key signatures in this pattern:
Bb, Eb, Ab, Db, Gb, Cb, Fb for both major and minor scales.
Bb major, which has two flats, has Bb and Eb in it’s key signature. Db major, which has five flats, has both the Bb and Eb in it’s key signature, as well as the Ab, Db, and Gb. Bb minor, having the same number of flats in it’s key signature as Db major, five, has the same key signature as well.
All Key signatures:
These diagrams were borrowed from this site:
http://library.thinkquest.org/15413/theory/intervals.htm#keys
