The System of Key Signatures
Key signatures use a specific system. Not just any note can appear in a key signature. There is an order and a logic that makes key signatures understandable. There are two varieties: sharp key signatures and flat key signatures (excluding C major, which has no sharps or flats). A key signature displays only sharps or only flats, never both. Within these groupings of sharps or flats, there is an order to how individual notes appear. Take a look at sharps and flats separately.
Do you remember reading that proper scale spellings also result in either sharps or flats? Scales and key signatures show you the same information, which is exactly why they help you understand more about the music.
Sharps appear in key signatures in a specific order: F#, C#, G#, D#, A#, E#, B#.
They always follow that order. If a key has one sharp, it will be an F#. If a key has two sharps, it will have F# and C#. It always works through the pattern in the same way. A great way to remember the order of sharps is to use a little mnemonic device:
Even though key signatures may appear confusing at first, most musicians would have a hard time reading without them. Constant flats and sharps placed throughout music are more challenging to read than a single key signature.
Just like sharps, flats appear in a specific order every time. Here is the order: B
There is also an easy way to remember the order of flats: Just reverse the mnemonic for sharps!
Learning the Key Names
If you stare at the circle of keys long enough, you might memorize what each key represents. There are a few tricks that can help you. On the flat side, the first key is F, which starts with the same letter as the word flat. After that, BEAD contains the names of the next four flat keys. That's a handy way to learn some of the keys. The sharp side is a bit harder. BEAD appears again on the right side. However, there are two little tricks you can learn for instantly naming a key just by looking at it.
The Sharp Key Trick
For any key that has a sharp in it, naming the key is as simple as following two easy steps. First, find the last sharp (the one all the way to the right). Once you've found and named the note that corresponds to the same line or space the sharp is on, go one note higher, and you've named the key. Look at FIGURE 5.4. The last sharp in this key is A#. Going one note above this is the note B. Five sharps is, indeed, the correct key signature for the key of B major. You can check the trusty circle just to make sure.
FIGURE 5.4 Name This Signature
The good news is that this trick works on every key that has a sharp in it. To find the name of a sharp key:
Name the last sharp, the one all the way to the right.
Go one note higher than the last sharp, and that's the name.
Unfortunately, it works only when you're looking at a key. If someone asks you, “How many sharps are in the key of E major?” you're stuck. For everything else, refer to the circle of keys and the order of sharps and flats.
The Flat Key Trick
The flat keys have a different naming trick. When you see a piece of music that has flats, find the second-to-last flat. The name of that flat is the name of your key. Look at the example in FIGURE 5.5. This key has two flats and the second-to-last flat is B This is an easy trick.
FIGURE 5.5 Name This Key
There is one exception: the key with one flat, F major. Since this key has only one flat, there is no second-to-last flat. In this case, you'll just have to memorize that F has one flat (which is B).
To find the name of a flat key:
Find the second-to-last flat (from the right).
The name of the flat note you find is the name of the key.
Just remember the exception—the key of F major has one flat and therefore the rule does not work for it. For the other keys, it works like a charm!
The Circle Moves in Fourths and Fifths
The name of this section says it all. The circle of keys is often referred to as the circle of fifths or the circle of fourths. The keys are arranged in the circle in a fairly logical way. The key of C, with no sharps or flats, sits squarely in the center, and the sharp keys move around the right side, each key increasing the number of sharps by one. The flat keys move to the left, increasing their flats by one as they progress.
Even before you memorize the entire circle of fifths, you can construct it using intervals. Draw a C at the top of a piece of paper. Now draw a few fifths to the right to name the sharp keys. To the left, draw a few fourths for the basic flat keys. Across the bottom of the page, spell the order of sharps from F, in fifths, and the order of flats from B, in fourths. As you move away from the key of C, each key increases by one flat or sharp (depending on which direction you move). You can match up the flats and sharps from the bottom of the page.
If you move to the right from C, each key is a perfect fifth apart. In addition, the order of sharps as they appear in the key signatures is also in perfect fifths starting from F#.
If you move to the left from C, each key is exactly a perfect fourth apart. Conveniently, the flats as they appear in the key signature are also a perfect fourth apart, starting from B.
Think about these two points:
Sharp keys move in fifths around the circle, and the sharps are fifths apart.
Flat keys move in fourths around the circle, and the flats are fourths apart.
When you move in one direction in the key circle, you move in fifths; when you move in the opposite direction, you move in fourths. Remember the explanation in Chapter 2 about interval inversion: A perfect fifth becomes a perfect fourth when inverted. A fifth up is the same as a fourth down. The same explanation applies to the order of sharps and flats. The sharps are spaced a fifth apart starting from F, and the flats are spaced a fourth apart starting from B. Interestingly, when you spell out all the sharps and read them backward (backward = inverted = in fourths), you get the order of flats.