The Co5's is the arrangement of the respective keys in order of
increasing sharps. It goes (F)CGDAEBF# (I learned it with an F at the
beginning; you'll find out why). C Major has no sharps, so let's start
there (I included F Major, cause that's how I wrote it in this
paragraph. Don't pay much attention to it yet.. you'll know why in a
second... hopefully).
[[(F Major) = 1 Flat]]
C Major = 0 sharps
G Major = 1 sharp
D Major = 2 sharps
A Major = 3 sharps
E Major = 4
B Major = 5
F# Major = 6
C# Major = 7
The 'F' before my 'C' in the Co5's I gave you above the list represents
the first Flat key (read below). It's also the first note to get
sharped in a key signature (that's why it's at the beginning). Whenever
you write a key signature in a Major key (aside from C Major) you will always start with a sharped F. Next would be a sharped C. Then G. Then D. So-on-so-forth.
To do a sharp key you start on the F, and then move down a 4th, up a
5th, down a 4th, up a 5th until you reach B Major, in which case you'll
go down another 4th (rather than up a 5th) to sharp the A. You do this
just because it looks nicer than having a sharp on a ledger line. The
pattern continues after that.
Now if you do it backwards starting at F you get: (C)FBEADGC. This is
in increasing flats. This is more of a Circle of 4th's, but it's
relevant, so i'll explain it. If you start at C Major, you get no
flats, then move up a 4th and you get F Major; 1 Flat. Up another 4th;
2 flats. It'll come out like this:
C Major = 0 Flats
F Major = 1 Flat
Bb Major = 2 Flats
Eb Major = 3 Flats
Ab Major = 4 Flats
Db Major = 5
Gb Major = 6
Cb Major =7
Now with the flat keys you will always first flat the B.
So F Major now has a Bb. Then for Bb Major, you flat the E as well as
the B. This pattern continues all the way until you reach Cb Major,
which is 7 Flats.
Now when you write a Flat key signature, you start at the B, then move
up a 4th, down a 5th, up a 4th, down a 5th, and that repeats until you
get to Cb.
A nice acronym to remember the Co5's is:
Fat Cats Go Down Alleys Eating Bagels
(C)
And for the Flat keys, I just remember F Bead GC. You'll get that eventually. Or there's also BEAD GCF (Greatest Common Factor)
i think this was somewhat helpful because i already know most of this ...its like a good refresher ...but i know if i didnt know any of this ...this would be a really good and to the point explination
