Sharp or Flat accidentals convention?

Sorry for the meaningless title ... what I'm trying to establish, is there a rule/convention for when one should notate an accidental as either A# or Bb (for instance)?

For whatever reason, I can "see" a Bb and play it without hesitation, but an A# in a score can make me stumble ... F#-Gb can be the same, there are probably others

I understand, in the world of "fretless perfection", A# can be a different note to Bb, but for us in the equal-temperament world they're much of a muchness

Any insight would be appreciated

Yes. There is a convention. It has to do with the circle of fifths. You add sharps, or take away flats, as you go to the right on the circle of fifths. You add flats, or take away sharps, as you go to the left on the circle of fifths.


So, whether you use sharps or flats depends on the key that you're in. C# is the same note as Db (There is actually a difference, but that's another story.) , but if you're in the keys of D, A, E, B, F#, and D# you use the C#. If you're in the keys of Ab, Db, Gb, and Cb, you use the Db.

If you're in a "flat key", that is one to the left of C Major on the circle of fifths, then you would indicate accidentals with a flat. If you're in a "sharp key", that is one to the right of C Major, then you would indicate accidentals with a sharp.

What the others have said. The convention is that you don't mix your sharps and flats in a given tune*. So if the key signature has any flats in it, then all the accidentals need to be flat; and likewise use sharp accidentals only in a key signature containing sharps (as for C/Am, if you start with flats, keep on with flats; if you start with sharps, keep on with sharps).

*The convention underlying that convention is that you can only use one letter once in a key - meaning you have to use all seven letters from A to G. You can't have a key, say A, written out as A B DbD E Gb AbA - even though those are the notes you'd be playing! The convention is that you have to write out the key of A as A B C#D E F# G#A.
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All that said, I do know exactly what you mean by A# vs Bb. Two stories. At our jam, one our favourites is "City of New Orleans" by Steve Goodman (great tune, btw, if you don't know it). We played it in the Arlo Guthrie key of F. The whole jam used to shudder to a halt on the last line of the chorus...
... because of that D#.

D#??!! What's D#???! It took ages to get round to changing that D# to an Eb

2nd story: the pUKEs were doing a tour of South-East English seaside towns, Brighton, Eastbourne and Hastings in particular. With an itinerary like that, someone on the tour bus reckoned we had to cover the Anti-Nowhere League/Metallica tune "So What?" with its opening line of "I've been to Hastings, I've been to Brighton, I've been to Eastbourne too" (for those of you that know what are the rest of the lyrics, don't worry, that's all I'm quoting!). By the time we'd got to the venue, they'd worked out the chords and explained them to the rest of us, thus: "In the chorus, it goes from F to A# to A - whatever A# is..." :-D

And the naming of notes or use of sharps or flats is connected to the scale and the chords created in that scale.

What gets goofy is when a song borrows chords (such as a secondary dominant, such as a D7 leading to a G7, leading to a C.

Ultimately, once you know the theory it all makes sense...but to most musicians, you still freak out when seeing an F-flat and wonder why they just don't call it an E.

Incidentally, in true intonation, a D-sharp and E-flat are not the same pitch; but our ears have adapted to hearing them as the same note (although I do know band directors who teach their students to play sharp or flat depending on the chord!).

You'll get a few different sounding answers. It boils down to what key you're playing in at the moment, (not necessarily the key of the piece you're playing).

The easiest way to think about it is that you always have all the 7 letters in any given scale, some of which may be sharpened or flattened.

To take your A# vs. Bb example.

In B major, for instance , you are not going to have a Bb because the letter B has already been used for the key note. B C# D# E F# G# A# (B).

If you are in F then there can't be an A# because there is an A natural as well. F G A Bb C D E (F)

You are right that in equal temperament Bb and A# have the same pitch but the standard notation system is based on Pythagorean tuning.

Dibblet said:

The easiest way to think about it is that you always have all the 7 letters in any given scale, some of which may be sharpened or flattened.

To take your A# vs. Bb example.

In B major, for instance , you are not going to have a Bb because the letter B has already been used for the key note. B C# D# E F# G# A# (B).

If you are in F then there can't be an A# because there is an A natural as well. F G A Bb C D E (F)

You are right that in equal temperament Bb and A# have the same pitch but the standard notation system is based on Pythagorean tuning.

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:agree: ...

Thanks people for all the replies ... I think I've got it ... if the tune is in D the accidental could be A# not Bb 'cos the key of D has two sharps, but if I was playing in F (one flat) the accidental could be Ab not G# ...

Have to practice some more

:music:

redpaul1 said:

The convention is that you don't mix your sharps and flats in a given tune*. So if the key signature has any flats in it, then all the accidentals need to be flat; and likewise use sharp accidentals only in a key signature containing sharps (as for C/Am, if you start with flats, keep on with flats; if you start with sharps, keep on with sharps).

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Only up to a point, though - minor keys can have a mix. G minor has two flats in the key signature but the F may also be sharpened. D7 (which contains F#) is used for both G major and G minor. This is a better way of thinking of it:

*The convention underlying that convention is that you can only use one letter once in a key - meaning you have to use all seven letters from A to G. You can't have a key, say A, written out as A B DbD E Gb AbA - even though those are the notes you'd be playing! The convention is that you have to write out the key of A as A B C#D E F# G#A.
________________

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Yes, once you are in minor keys or various chromatic harmonies it can be less clear.

FWIW- I always recommend this book http://www.edly.com/mtfpp.html

It has a lot of good info, yet is very easy and fun to read, which one can rarely say about a theory book!

That happens to me too. Once you have to stop to think about it you are lost. That is what a pencil is for. You take the pencil and cross out the A# and write in bold letters a Bb. Because all that counts when you are playing the song is that you hit the chord.

EDW said:

Yes, once you are in minor keys or various chromatic harmonies it can be less clear.

FWIW- I always recommend this book http://www.edly.com/mtfpp.html

It has a lot of good info, yet is very easy and fun to read, which one can rarely say about a theory book!

Click to expand...

This was good news and off I went to look at it. The down side for me (in the UK) is that some American and British music theory is not quite the same, I don't know whether it's just note values that are expressed differently or if there are other differences too.

Music theory books are generally unbelievably dry and I find them really offputting; books that engage and entertain the reader instead whilst transferring knowledge feel near impossibly hard to find. If anyone knows of an engaging UK equivalent then I'd be very pleased to hear about it.

Graham Greenbag said:

...The down side for me (in the UK) is that some American and British music theory is not quite the same, I don't know whether it's just note values that are expressed differently or if there are other differences too.

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I can't think of any significant difference except the names for note lengths. There are some differences in terminology between the classical and jazz worlds though. Then when you get into really advanced stuff most theorists on all sides seem to invent their own terminology. I'm thinking of Hugo Riemann, Arnold Schoenberg, Ernst Levy, George Russell, Steve Coleman. You'd probably find all of them incredibly dry.

Dibblet said:

I can't think of any significant difference except the names for note lengths.

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Trying to decide what a "measure" was had me going for a while ... I've not yet needed to remember the difference between a crotchet and a quaver, let alone any trans-atlantic equivalents.

Descant and soprano, treble and alto ... there are a few other terminology differences, nothing that stops me playing the music!

:music:

Rllink said:

That happens to me too. Once you have to stop to think about it you are lost. That is what a pencil is for. You take the pencil and cross out the A# and write in bold letters a Bb. Because all that counts when you are playing the song is that you hit the chord.

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For hitting the chord, that's fine ... I was more interested in preparing notation that might need to be read by other people ... apparently I shouldn't have a Bb accidental in the key of D or G, for instance, or a C# accidental in the key of F!

All things to remember!

:music:

kypfer said:

For hitting the chord, that's fine ... I was more interested in preparing notation that might need to be read by other people ... apparently I shouldn't have a Bb accidental in the key of D or G, for instance, or a C# accidental in the key of F!

All things to remember!

:music:

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Sounds good. I didn't understand what you were aiming at. I just play 'em.

ubulele wrote:

Once you talk about chromatic alterations, the spelling should reflect the purpose of the alteration, regardless of whether you're in a sharp or flat key (and what do you do when you're in C, which is neither a sharp nor flat key?) Those alterations also include chord roots: a #I chord and a bII chord map to the same physical chord, but they have different harmonic senses and uses. In the key of D, the former should be named D# whereas the latter should be named Eb, despite that D is a "sharp" key.

Similarly, if you're writing standard notation and you have two chords C7b5 and C7#11, you might use voicings with the exact same pitches, but the b5 should most properly be written as a Gb whereas the #11 should be written as an F#.

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Well ... I needed to re-read that a couple of times for it all to make sense, but thank you, I think I've got a complete picture now

kypfer said:

Thanks people for all the replies ... I think I've got it ... if the tune is in D the accidental could be A# not Bb 'cos the key of D has two sharps, but if I was playing in F (one flat) the accidental could be Ab not G# ...

Have to practice some more

:music:

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You got it.