Why does musical notation have double sharp and double flat symbols

[JVS]

Wouldn't it be easier to write B double flat as A natural and F double sharp as G natural?

[jpgray]

1. F double flat would be E flat.

:)

[JVS]

3. Oops, I fucked up. I meant to say B double flat

[bbernardini]

2. It's for consistency with scale labeling conventions.

If you didn't use double sharps and flats in the keys with higher numbers of sharps and flats, you wouldn't get the line-space-line-space standard.

[JVS]

4. Would you mind elaborating?

[bbernardini]

12. Gladly. I wasn't very clear before.

I was kind of hurried.

Scales are supposed to be written in alphabetical order, starting and ending on the same letter, with all of the other letters in between. Let's take G, for example.

G-A-B-C-D-E-F#-G

Let's change it to G#:

G#-A#-B#-C#-D#-E#-F##-G#

In order to get the proper interval relationships between the notes, and still retain the GABCDEFG order, we need to use a double sharp on F.

Of course, the whole point is moot if you just write in Ab instead. :)

[KT2000]

5. I always thought it was dictated by

the key in which the piece was written, a B double flat is used when the A would have been a flat

:shrug:

[JVS]

6. I thought about that too for a moment, but you could use A with the symbol

that indicates natural rather than what the key symbol dictates.

[St. Jarvitude]

9. Having flats and naturals and sharps all over the place can clutter music

You could write a scale in a piece of music that changed clefs every measure, but why would you want to?

It's a bit more extreme than the case of double sharps and flats, but readability is very important when writing/publishing music.

[KT2000]

14. Know Ethelbert Nevin?

I always wondered if he cluttered up his music with notations (lots of double sharps and flats) beause it was the proper form or if he had not thought it through thoroughly.

[St. Jarvitude]

7. There's a good reason

It's hard for me to explain it without a pen and paper,
though. 

Essentially, if I am writing music with a minor scale run,
while I'm in another key, it's useful sometimes to use a
double sharp or flat.

[JVS]

8. It is possible to do without double flats and sharps though, correct?

Although accurate reading is the goal here which may make double flats and double sharps a better solution

[Karenina]

10. They are useful in a score ( chord recognition)

or if consistent in a player's part, being part of the key's visual landscape. It's a context thing. Having an A# tied to a Bb is useless and confusing for a "single liner."

[Chipper Chat]

11. It's a scale step thing...

There are 8 notes in a scale, and notes on a staff should comply with that. For instance "Put 'Em Back" from the Broadway musical Lil Abner was written in the key of C-flat. So the 8 notes are C-flat, D-flat, E-flat, F-flat (which shouldn't be written on the page as E-natural because it is on the same line as the 3rd scale step (E-flat)), G-flat, A-flat, B-flat, C-flat. If in the melody you want to lower the 7th degree in an 8-7-7flat pattern it would be written as C-flat, B-flat, and B-doubleflat.
Knowing how this works it is easy to understand the double-sharp/flat concept and how it must be written.
Clear as mud? Well, it's the best I can do.

[Karenina]

13. It's the visual landscape

of a particular scale. It's about READING. Think diacritical marks.

[leftofthedial]

15. what does easy have to do with it?

wouldn't English be easier without all those vowels?

[DieboldMustDie]

16. As I recall they tend to appear more often in minor keys.

e.g. a B major scale is B C# D# E F# G# A# B and its relative minor, G#^m is G# A# B C# D# E F# G#, but that's the natural minor. The melodic minor scale has the 6^th and 7^th degrees of the scale raised a semitone when ascending the scale which gives us G# A# B C# D# E# F## G#, though it's the same as the natural minor descending; the harmonic minor has a major 7^th, so it's G# A# B C# D# E F## G#. By the way, I haven't had a music theory class in more than 20 years, so my memory is a little sketchy.