Key Signatures

Apr 10

Key Signatures

Beginner, Theory, Arranging, Composition, Articles Add comments |

An article by: Tyler Oakleaf

Many people cringe at the mention of key signatures. In actuality, a key signature can be a huge help and a great short cut to memorizing intervalic relationships, scale shapes, and more.

The key signature can serve several, very useful purposes by simplifying the work needed to:

Identify tonal centers (ex: the key of a piece).

Define “Perfect” and “Major” intervals.

Identify harmonic relationships.

Why Key Signatures?

If you asked the average person to picture a key signature, most people would probably come up with something like this. And while these are key signatures, that’s not where the buck stops. Because as was mentioned earlier, a key signature tells us so much more then just what the key of a piece is.

A key signature is really trying to clue us in on what tones we need to alter (flat or sharp) in order to create only perfect and major intervals between the root of the key and all seven other intervals.

Why care about perfect & major intervals?

(For a more detailed explanation of intervals check out the our lesson, creatively titled “Intervals”)

By identifying all of the perfect & major intervals we give ourselves a point of reference upon which we can base all other intervalic relationships. You could almost consider perfect and major intervals “comparison operators.” You could almost think about them like the lines on a football field. There can often-times be great distances between different intervals, just as a football field can span a great distance. Without grid-lines (the perfect & major intervals) to let you know where you are it is near impossible to have any sense of distance. Can you imagine having to re-measure the distance from the goal line before every down to see if you made a first?

Finding your inner key signature.

While there are many ways to derive a key signature, I find the following method the simplest.

This is the is a graphic depiction of the infamous circle of 5ths/4ths. Here’s how it works:

The inner ring is the circle itself.

If you read clockwise the notes will move upward by a perfect 5th. (C -G -D -A -E -etc…)

If you read the circle counter clockwise the notes will be moving down by a perfect 4th. (C -F -Bb -Eb- Ab -etc…)

If this doesn’t make sense to you just count on your fingers and you’ll get it. -ex: (c, d, e, f, g)= 5

The notes on the outside of the ring correspond to the key signature (altered tones) of the key of the pitch inside the circle.

Examples:

The key of ( C ) has ( No ) altered tones (sharps & flats).

The key of ( G ) has ( 1 ) altered tone(sharps & flats) ( F# ) .

The key of ( Bb ) has ( 2 ) altered tones(sharps & flats) ( Bb, Eb ).

Some Interesting things to note:

Hopefully it has become obvious to you that there are many patterns within this circle that you can use to help you to better understand this circle. For instance did you catch on to the fact that the order of the alterations (sharps & flats) was consistent throughout all keys? You might also have noticed that the order of sharps followed the circle of 5ths starting on the note F, and the order of flatted keys followed the circle in the direction of 4ths starting on the note Bb.

You should try your best to take advantage of these patterns whenever possible.

Example:

If you are in any “sharp key” you can assume the note F# will be an alteration within the key.

The last sharp in a key is always a half step below the root of a “sharp key.”

The second to last flat is always the root of a “flat key.”

Things to keep in mind:

Key signatures are useful for more then just finding keys. They can also help identify major & perfect intervals, which can be extremely useful for identifying intervalic relationships.