F double sharp is enharmonic to G, not G#. So the note you need to play is a G. A sharp or flat means you raise or lower the note by one half step.

Is F double sharp the same as G?

The effect of the double sharp symbol raises the pitch of the indicated note by two semitones (two half steps). The resultant pitch would sound the same as the pitch “G”.

Why is F double sharp not G?

It sounds like one, but we don’t write it that way to make our notation consistent. TL;DR, we use double sharps and flats to preserve letter names of notes, and we do this because it makes our notation more consistent and easier to analyse.

The letter f stands for the Italian word forte, which means “loud.” The composer adds these types of instructions to help the musician to portray the mood of the music. A double p, pp, stands for pianissimo, which means “extra quiet.” A double f, ff , stands for fortissimo, which means “very loud.”