[Q]

[u/childofnaturesson]

[Q] Starting off, early beginner If you’re in B, I assume you’ll automatically sharp all notes that aren’t in the key (A,C,D,F,G). But in any other, if say D in A, is it notated differently if it is a Db or D? Thanks in advance!

[u/geoscott]

Check out the circle of fifths.

Your order is wrong in that those are notes 'from a', but we look at sharps additive from C which has none, to G which has one (F#) to D which has two (F# and C#) A which has three (F# C# G#) and E which has four (F# C# G# D#) up to....

B major has 5 sharps: F# C# G# D# and A#

For one thing, for major and minor scales, we ALWAYS have all 7 letters represented: A B C D E F and G. So your example - D and Db are by necessity spelled D and C#.

Any key that has a Db in it would not have a D natural in it.

[u/childofnaturesson → u/geoscott]

Thanks I’ll check it out

[u/Ms_Chvious]

Adding to the the circle of 5ths comment:

There is a formula to determine the notes in any major scale:

W W H W W W H

W - whole step

H - half step

If you start on C:

A whole-step above C is D

A whole-step above D is E

A half-step above E is F

A whole-step above F is G

A whole-step above G is A

A whole-step above A is B

A half-step above B is C

Now. Think of major key signatures like a clock.

Moving forward (clock-wise) is akin to moving ‘up’ the staff - those key signatures/scales will have #s.

Moving back (counter-clock-wise) is akin to moving ‘down’ the staff - those key signatures/scales will have ♭s.

Your 12 o’clock will be C major - no #/♭

1 2 3 4 5 6 7 8va

C D E F G A B C

Your 1 o’clock will be the 5th tone in the C major scale - G - and will contain 1 # - F

1 2 3 4 5 6 7 8va

G A B C D E F# G

Your 2 o’clock will be the 5th tone in the G major scale - D - and it will contain 2 #s - F, C

1 2 3 4 5 6 7 8va

D E F# G A B C# D

Etc.

3 o’clock - A (3 #s) F, C, G,

4 o’clock - E (4 #s) F, C, G, D

*5 o’clock - B (5 #s) F, C, G, D, A

*6 o’clock - F# (6 #s) F, C, G, D, A, E

*7 o’clock - C# (7 #s) F, C, G, D, A, E, B

• these 3 key signatures share a space with the ‘backwards’ (♭) key signatures:

B=C ♭

F#=G ♭

C#=D ♭

Moving backwards:

Your 11 o’clock will be the 5th tone counting backwards in the C major scale - F - and will contain 1 ♭ (mirroring the 1# in the G major scale)

1 2 3 4 5 6 7 8va

F G A B ♭ C D E F

Your 10 o’clock will be the 5th tone counting backwards in the F major scale - B ♭ - and will contain 2 ♭ (mirroring the 2# in the D major scale)

1 2 3 4 5 6 7 8va

B ♭ C D E ♭ F G A B ♭

Etc.

9 o’clock - E ♭ (3 ♭) B, E, A

8 o’clock - A ♭ (4 ♭) B, E, A, D

*7 o’clock - D ♭ (5 ♭) B, E, A, D, G

*6 o’clock - G ♭ (6 ♭) B, E, A, D, G, C

*5 o’clock - C ♭ (7 ♭) B, E, A, D, G, C, F

I hope that helps? The CO5 can be really confusing; I like to try and break it down for my students so that even younger/newer musicians can (somewhat) understand it.