text: concerning sharps and flats-- what to do when a note is sharped even though it is already sharp in the key sig i'm learning beethoven's moonlight sonata and i'm at a part where there's an f double-sharp. since f is already # in the key signature, do i start at f# and go to g# or do i start at f natural and go to g? also, in measure 34, there is an f double-sharp, then a regular f, then another f double-sharp.  is the second f natural or does the double-sharp carry for the whole measure?  if so, why is the third f double-sharped again? sorry if this is confusing; it's hard to explain in words. thanks in advance. if there's already a # in the key signature, it doesn't matter.  when the f is double sharped, you start from f natural and go up two to g natural.    in measure 34, the first f double sharp means that all f's (on that line) will be double sharped.  but the third f is one octave above the first f, so it has to have a double sharp as well.  double sharps carry through the measure, but only at their pitch.  so if you have a note that is the same tone but different pitch, then it has to be double-sharped again.  so if your f one octave middle c is double sharped, then all f's one octave above middle c in that measure are double sharped and don't need the sign in front of it.  but if you have an f two octaves above middle c, then that has to be sharped.  hey, if worst comes to worst, just listen to the cd and play by ear.  if it sounds weird, then try something else...good luck!