Musical Key Signatures

Key signatures are a theoretical approach to knowing what scales, chords and ideas you can play during a song without worrying about playing wrong notes. You can use the chords in a song to figure out what key it is in or if you are using regular notation you can simply look at how many sharps and flats or flats there are at the beginning of the clef. Key signatures can be major or minor and be any of the 12 notes of music, such as A minor or C major. Key signatures can give a certain feelings or moods to a song as well, much like major and minor chords.

Circle of Fifths

An easy way to figure out what key your playing in is to use the circle of fifths chart. At the beginning of a sheet of notation music there are a group of sharps or flats. The lines these symbols are on affects the notes on that line for the duration of the song or until the key changes again. To use the circle of fifths chart you can just count how many sharps or flats there are on the staff and compare it to the chart. If your music has 1 sharp, it is F major. Make sure if there are sharps, you use the right side of the chart, since the left side is for flats. If there are 3 flats, the key is Eb major. The numbers inside the circle correspond to the number of sharps (right side numbers) and the number of flats (left side numbers). There are a lot of different style of the circle of fifths charts so make sure you know what chart your looking at and know what everything means.

Keys and Chords

You can also tell what key you're in by studying the chords you're playing. When you're playing just power chords using the root, 5^th and 8^th notes, you can judge by the root notes of the chords what key you're in. For example, using the chords C5, D5, G5 you could be in the key of Gmaj OR Cmaj since both keys contain the notes C, D, and G. To really narrow down the key you're in, you have to use chords that contain more notes. If you add in the 3^rd to each chord it only leaves the key of Gmaj because the third of Dmaj is an F#, which doesn't exist in the key of Cmaj. This shows why keys are important. If you're playing these three chords, C, D, and G, you could maybe get away with playing a Cmaj scale for the melody by leaving out some notes, but it would be more to your advantage to use all the notes of the Gmaj scale.