In this lesson, we are going to pick up again with the concept of key signatures. In our last lesson, we worked out all the key signatures that involved sharps. This time around, we are going to identify all the flat key signatures. And our method changes slightly. For starters, the set of notes we will be memorizing this time takes the form,

B, E, A, D, G, C, F

In reverse order, we noticed that the interval distance between each note was a perfect 5th or seven half steps. This time around, we notice that the distance between B and E, for example, is only 5 half steps. This is of course an interval whose length is a fourth. The interval distance from E to A is also a fourth, from A to D is again a fourth and so on. So, in this context, the circle of fifths is sometimes refered to as a circle of fourths when considering flat keys. Again, the key of C is a special key that contains no sharps and no flats. And last time I asked you to memorize the key of F as having a B flat. Let's use our Ionian mode shape again and prove that the key of F truly does contain a B flat.


THE F MAJOR SCALE
F, G, A, B flat, C, D, E

E1, E3, E5
A1, A3, A5
D2, D3

And as you will notice, A1 is in fact a B flat in the key of F major.

Our rule of thumb is to take any note in our list, move one note to the right, and all the notes to the left and including that note are the flats in the key of interest. Confused? Well, there is no reason to be, because the idea should be come crystal clear after a couple of examples.

Since our first note is B, we move one note to the right in our list (which is E), and we conclude that the key of B flat has a B flat and an E flat.

THE B FLAT MAJOR SCALE
B flat, C, D, E flat, F, G, A

E6, E8, E10
A6, A8, A10
D7, D8

And as we can see, E6 is B flat, and A6 is E flat, with a B flat on D10 to complete the octave. So, our method works.

Note that in a B major scale, there is no B flat. So, since we have a B flat, we must identify this as the key of B flat, not as the key of B. None of our flat keys will contain the natural form of the root tone. That is something to pay attention to as we construct the flat keys.


The next note in our list is E. The note to the right of E in our list is A. So, the key of E flat major has a B flat, E flat, and an A flat.


THE E FLAT MAJOR SCALE
E flat, F, G, A flat, B flat, C, D


E11, E13, E15
A11, A13, A15
D12, D13

And as we can see, E11 is E flat, A11 is A flat, and A13 is B flat, with D13 giving us an E flat on the octave. So, our method worked again.


The next note in our list is A. The note to the right of A in our list is D. So, the key of A flat major has a B flat, E flat, A flat, and a D flat.


THE A FLAT MAJOR SCALE
A flat, B flat, C, D flat, E flat, F, G

E4, E6, E8
A4, A6, A8
D5, D6

And we can see that E4 is an A flat, E6 is a B flat, A4 is a D flat, and A6 is an E flat, with D6 being an A flat to complete the octave. So, our method worked again.


The next note in our list is D. The note to the right of D is G. So, the key of D flat major has a B flat, E flat, A flat, D flat, and a G flat.


THE D FLAT MAJOR SCALE
D flat, E flat, F, G flat, A flat, B flat, C

E9, E11, E13
A9, A11, A13
D10, D11

As we can see, E9 is D flat, E11 is E flat, A9 is G flat, A11 is A flat, A13 is B flat, and D13 is the D flat octave. So, our method works again.


The next note in our list is G. The note to the right of G is C. So, the key of G flat major has a B flat, E flat, A flat, D flat, G flat, and a C flat.


THE G FLAT MAJOR SCALE
G flat, A flat, B flat, C flat, D flat, E flat, F

E2, E4, E6
A2, A4, A6
D3, D4

As we can see, E2 is G flat, E4 is A flat, E6 is B flat, A2 is C flat, A4 is D flat, A6 is E flat, and D4 is the G flat octave. So, our method works again.


The next note in our list is C. The note to the right of C is F. So, the key of C flat major has a B flat, E flat, A flat, D flat, G flat, C flat, and an F flat.


THE C FLAT MAJOR SCALE
C flat, D flat, E flat, F flat, G flat, A flat, B flat

E7, E9, E11
A7, A9, A11
D8, D9

As we can see, E7 is C flat, E9 is D flat, E11 is E flat, A7 is F flat, A9 is G flat, A11 is A flat, D8 is B flat, and D9 is the C flat octave. So, once again our method works.


The interesting thing to note at this point is that the key of C major is the key that has no sharps and flats. The key of C sharp major has all sharp notes. And the key of C flat major has all flat notes. It's funny that the mathematics behind the music theory works out that way. But, now you know how to determine which flats belong to which flat key signatures.

For homework, I would like you to add these key signatures to your notes for future reference. Also, you can check the video section on my profile under the content section for some videos on the circle of fifths and listen to others talk about key signatures.


Corey J. Bray