Hey everyone,

Pretty simple question really, but something I've been wondering. Why would a composer choose to use something like a double sharp or double flat? Why wouldn't they just write the note above? Wouldn't that be easier to read?

Just curious if there is a reason or if it's just preference.

Thanks for any responses...

There is a reason - and it is due to the theoretical relationships between and within keys. Here's an example - say you're writing a piece in B major, and you want to notate an augmented triad on I. The notes to that chord are B, D#, and Fx. It would be incorrect to use B, D#, and G, because that would equate to steps 1, 3, and 6 of the scale when the triad must be steps 1, 3, and 5. This is why the F double-sharp must be used in this case.

That's just one example, there are plenty more.

Here's another weird one - in a piece I was writing, I wanted to notate a section where it was simultaneously in F# major and F# minor. As such, the A in question needed to be both sharped (for the major) and natural (for the minor). To do this I needed to split the stem and notate AN and A# on the same stem. It would have been much easier to use A natural and B-flat, but from a theory perspective that would have been incorrect (you just don't notate F# major as F#-Bb-C#...) So its for theory reasons that you see some things notated that might otherwise be notated in an easier manner.

It depends on the context of the note. For instance if you were going to write say a C diminished seventh chord, the proper spelling would be C Eb Gb Bbb.

To someone familiar with music theory, this is actually easier to read, mostly because it maintains the overall shape of a 7th chord, that is, ignoring flats or sharps, it would look the same as a C dominate 7th chord (C E G Bb), or a C major 7th chord (C E G B). All of those chords have the note names C E G B with varying flats.

If a C diminished 7th was spelled C Eb Gb A, it would actually look like the first inversion of an A diminished 7th chord, thus possibly screwing up the "grammar" of the song and otherwise confusing things.

But in cases where the note is more isolated, it can often be composer preference. I've often used them in my piddly compositions to maintain similar shapes in sequences of notes. I have no idea if that is "correct" usage or not, I don't know as much as I like to think I do.

Excellent responses guys. Thanks for the insight. That makes a lot of sense. I guess I'll just need to look at the step relationships a little closer when I see them in use.

Sometimes a change in notation makes things easier to read. For example, the chord AbCEbGb (Ab7) looks like it should be the dominant of Db and thus is the correct spelling if resolving to Db. If it's written AbCEbF#, then it's a German Sixth resolving to a G chord or a C64 then a G. Similarly for AbCDGb vs AbCDF#; the first is a dominant with a flat fifth and the second a French sixth.

There's a sort of rule of thumb that sharped notes rise and flatted notes fall in resolution. (Similarly, augmented intervals expand and diminished intervals contract.) Following these schemes makes things easier to read (and analyze for that matter.)

Double sharps and double flats allow one to notate these tendencies.

Another case is when a piece is transposed to a different key.

If a melody deviated from the key's diatonic scale (as most do) a piece in C might have a melody which involved a D#, which is an accidental in C. If you transposed the piece to a different key, like E, that note might happen to land on a note which is already sharped in the key signature. So to avoid showing it in a different relative spot on the staff, you would call it a double-sharp. The second scale tone in the key of E is F#, so the same piece transposed to E would show that note as Fx.

Don
Kansas City

Something I don't think that's been mentioned yet:

It's all about scales (this is where it all starts in reality, as far as I'm concerned):

C major is CDEFGABC, fair enough...
F# is F#G#A#BC#D#E#F#, fair enough...

If, however you wanted to use an "imaginery" scale like... G# (Ab in reality) then you would get:
G#A#B#D#E#FxG#. Scales need to go from note to note, not skip notes, or repeat notes. There's no other way to notate this, when starting in G#.

Now, why on earth would someone start with G# and not Ab? Probably because he was in C#minor in the first hand I guess and the V is G# maj (7th or no 7th). A small modulation there, and you're set to go...

If you write tonal music it only makes sense in this way. If you are not tonal then the only reason would be to accomodate some kind of natural-flat/sharp clash, as mentioned by 8ude...

Thanks for all of the responses guys.

I guess there will also be a similar theory related reason for time signatures? Why would someone write in 3 / 8 as opposed to 3 / 4?

let say i'm writing a peice that at 140 bpm in 3 / 4 and a second peice at 70 bpm in 3 / 8.

wouldn't these peices be basically the same? Is there a theoretical reason to choose one over the other?

sorry for such n00bish questions.

There is no difference in (for example) 3/8 @ 90 and 3/4 @180. The primary reasons for choosing a time signature are ease of reading and convention. It is conventional that a waltz is in 3/4 (although phrases usually extend over measure pairs) and a gigue (jig) in 6/8. A polonaise in traditionally in 3/4 but with differing phrase structure than a waltz.

There are minor differences in 2/4 and 4/4 though. Some tango composers write in 2/4 but phrase as 4/8. Others write in 4/4. Either way is OK.

Much of the older music has been translated so that a breve (meaning short) is written as a quarter note, just to make reading easier.

If the notes are written the same, you guys are backwards, I think. Quarter notes at 140 would result in the music being four times faster than eighth notes at 70!

Don
Kansas City