Question: What are Double Accidentals?
Before we go to double accidentals, let's review what are sharps, flats and half steps. A half step is to move from one note to the next note either upwards or downwards. To move a half step upwards or one note upwards is to sharp a key. To move a half step downwards or one note downwards is to flat a key. Flats and sharps are also called accidentals.
Answer:
A double accidental means to raise or lower a note two half steps which is equivalent to a whole step. A double sharp raises the note 2 half steps. A double flat lowers a note 2 half steps.