9

I’m trying to play Toccata by Debussy and the piece is in the key of E. In the sheet music, the F has a double sharp next to it, so that means I would be playing a G sharp. When I looked at the synthesia, it was playing a natural G. I’m not sure if I’m wrong or the synthesia is but I highlighted the section in yellow.enter image description here

enter image description here

1
  • Tangentially, the enharmonic notation seems surprising here: surely the D-naturals in the first measure would make more sense as a C-double-sharps, fitting into A-sharp major and resolving into the D-sharp major on the next beat?
    – PLL
    May 18, 2020 at 22:52

4 Answers 4

35

Accidentals affect the basic note - if you like, the white key on the piano.

So, regardless of the key signature - which permanently changes certain notes (here F, C, G and D♯), the double sharp applies to a basic F note, making it Fx (F♯♯) or F double sharp.Taking it up two semitones, so it looks like a G note on piano.

What it doesn't do is take the F♯ notated in the key signature, and then double sharp that!

3
  • 8
    This is correct. The double-sharp accidental replaces the sharp in the key-signature -- it is not in addition to the sharp.
    – Rosie F
    May 17, 2020 at 7:04
  • This must have been the wrong premises of OP. key signature plus double sharp = 3 semitones up! Tim's answer is destroying this error most best. May 17, 2020 at 9:28
  • 2
    Music notation is well adapted to support sight reading and when you see a double sharp you only double sharp the F forgeting whatever F was previously. May 17, 2020 at 11:58
7

" In the sheet music, the F has a double sharp next to it, so that means I would be playing a G sharp."

No. Accidentals aren't additive. We don't tot up the F♯ in the key signature plus the accidental double-sharp to make a triple-sharp. It's just F double-sharp. Played as G.

5

F double sharp is enharmonic to G, not G#.

So the note you need to play is a G.

3

A sharp or flat means you raise or lower the note by one half step. Or, as semitone. When a note has a small cross-like sign next to it, like you have there, you do this twice by raising it a whole step, two semitones. F > F# is one, F# > G is another.

Interestingly there is another double sharp there, before the bar line. In order to cancel a double sharp there would need to be a single sharp there (you did once also need a natural sign but this is no longer necessary).

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.