Music Theory For Bass Guitar - Key Signatures & The Cycle of Fifths 

That's what I use to remember.

4 years later are you professional yet XD

5 years are you a pro bassist

music theory isn’t an art but what music theory creates is definitely art

+Drew Stephens I'll share what I've learned, if you don't mind. It makes is easy to tell what key a song is in -- if you see 3 #'s, you know it's A major. It's really helpful when you get into what I call the 'weird' key signatures, like 5 flats (D flat major), 6 sharps (F# major), where almost all the notes in the key are flat or sharp. But I usually only see the weird key signatures in classical music. The last sharp you see in the key signature (to the right) is always the 7th note of the key. E.g., F# is the 7th of G major, C# is the 7th of D, etc. The beauty of the Cycle of Fifths is that pattern stays the same thru all the keys with #'s. So if the last sharp is A#, you know the key is B major. With flats, the last flat you see is the 4th note of the key. So B flat (1 flat) is the 4th of the key of F major. E flat (2 flats) is the 4th of B flat major, etc. I find it helps to focus on the last sharp or flat in the key signature to keep me from confusing what key I'm in.

I've got the same dilema (this equivalence of B flat and A sharp). Mark, could You help us to understand this issue? Thank You.

+B. Key It depends on the key you are in. All the keys follow alphabetical order from the tonic, and no letter can be used twice. E.g., the key of B major already uses a B natural, so it can't have a B flat also. So it uses A# instead. The key of F major already has an A natural, so it can't have an A#, it uses B flat instead.

Since C has no sharps or flats, you go to the fifth step of the C major scale which is G. G has one sharp, which is F. The fifth step of the G major scale is D. D has 2 sharps, which are F and C. This pattern continues around the circle of fifths.

That’s very helpful. Thanks for sharing!

Because A is already in the key of F, you can't have 2 of the same letters in any key, like how A is already in F, you would have to say B flat instead of A sharp. This is called "enharmonic equivalence" when 1 note can have 2 different names, it all depends on what key you're in to know which name to use

There is a B#. Just as there is also an E#, F##, G##, C###, D### etc. It's just that B# is enharmonically the same as C. B# is not very common but you do see it occasionally. The most common use is as the seventh in the key of C#. C#, D#, E#, F#, G#, A#, B#.