Category: Music Theory
Let me paint a picture for you: You are a detective working on a case involving a musician who has planted a bomb somewhere in your city. He has left you clues as to where the bomb is located. One of the clues is a piece of sheet music. You need foil his plot, so you need to find out everything you can about this piece of music.
HOW DO YOU FIGURE OUT THE KEY?
First clue: The key signature
Your key signature can narrow down your search, based on the circle of fifths. Remember each key signature can identify one major key or one minor key. Remember this graphic?
In the above graphic, the major key names are on the outside of the circle in RED, and the minor key names are on the inside of the circle in GREEN. So lets take an example of a key signature with 3 flats. According to our handy-dandy donut of fifths, the key can either be E flat major, or C minor. BUT WHICH IS IT?!!
In minor keys, the seventh note of the scale will often be raised by an accidental. Do you see accidentals throughout the piece of music? Does it occur on the 7th note of the minor key identified in step 1? If so, you may have a minor key on your hands. Use this method of identification in combination with the one above in order to identify whether you have a minor or a major key.
What chord/note combination does the song start and/or end with? This can often give you a clue as to what key the piece of music is in. Often music will start and/or end on the tonic. Note that this is not a failsafe method of identifying the key of a song. Rather it can be used in combination with the two methods above.
Play the music. Does it sound minor to you? Then it could be minor. Don’t rely on this to identify the difference between minor and major keys, especially if you are a beginner.
By combining the techniques described in all four clues, you should be able to find the bomb and save your city from disaster. You may want to practice a few times, just to be safe.
Our city thanks you!