Accidentals

[a12]

What is the rule when to use # or b when making a note
different from the key you are in?
If I am in the key of C, would you use G# or Ab ?

[Jim Broyles]

As I understand it, you use #'s for the sharps keys - G, D, A, E, B, F#, and b's for the flats keys - F, Bb, Eb, Ab, Db, Gb, and the appropriate one for what the chord is named: Caug5 uses G#; Cmaj7b5 would use a Gb. However, I ran into a piece of music at church this past Sunday which used an Eb in the key of G, (one sharp) and when I asked our music major piano player, she told me that it was because it was a descending chromatic run starting on E. Didn't make that much sense to me, but I defer to her degree.

[a12]

I think there is more to it than whether the key is sharp or flat. ??

[Bruce Clausen]

It can get very complicated, but normally: #when an accidental is a sharp, it's moving up (G# goes to A); #when it's flat it's going down (Ab goes to G). #As jb's piano player said. # But sharps that are scale notes in sharp keys and flats that are scale notes in flat keys are not accidentals, and so this doesn't apply to them. #Often the chord that's sounding decides the question: #in the key of C, an E chord will have G#, an F minor chord will have Ab. #And sure enough, when the chord changes, nine times out of ten the sharp note will rise, the flat will fall. #--BC

[Seth Austen]

How a note is perceived can impact what you call it. In C, if I play an Eb, it's the minor third, if I call it a D#, it's the #9

Seth

[BluegrassGirl26]

huh? What are accidentals even used for? I learned them about two years ago and still haven't found one in a jam session or any song for that matter. Maybe I just don't understand them and they really are there .

[John Flynn]

What are accidentals even used for?

An accidental is simply a note that deviates from the sharps or flats called for in the key signature. The consist of sharps, flats and naturals. There are melodies that just have accidentals in them. Then are also chromatic runs that are used in improvization, as mentioned before, and chords. So if you were, for instance, playing a tune in A that had a C chord in it, C is not in the A major scale. So the root of that C chord would be an accidental.

[arbarnhart]

I don't see blues in full notation often, but if it were, it would probably be chock full of accidentals. The 7th that gets played so much is not the major 7th but rather the dominant 7th, which is the major 7th flatted. In C, that is a bB. But the key signature for C has no sharps or flats, so a bB is an accidental, I think. I could get corrected...

EDIT - I had a book of blues songs right in front of me. It is chords and song melody, and I mostly looked at chords before. Flipping through looking at melody lines, pretty much every page has several accidentals.

[kww]

Believe me, once you try to play a diatonic harmonica, you will learn how often accidentals happen. Every time you hit one, you have to bend the reed to get it. Bending a harmonica reed to play an in-tune half-step off of the standard pitch is non-trivial. It doesn't take long to learn how to play a harmonica for tunes that have no accidentals, but it takes a long time to learn how to play anything that has them.

[dough-re-mi]

A related question: I see the blues scale often notated as 1 b3 4 #4 5 6 b7 8; is there any reason #4 is used instead of b5?

[Seth Austen]

I consider it a b5.

Seth