Accidentals

Usually in sheet music, we use three main accidentals: the sharp, the flat and the natural.

The sharp accidental (♯) raises a note’s pitch by a half-step. A note with a sharp accidental will sound a semitone higher than the same note without a sharp. For example, when notated with a sharp accidental, a G on the piano would become a G♯. Instead of playing the G, you would play the note a half-step higher than G# which is the black key to the right of the G on a modern piano. 

The flat accidental (♭) lowers a note’s pitch by a half-step. Any pitch with a flat accidental will cause the note to sound a semitone lower than the same note without the flat. Again using the piano as an example, a G notated with a flat would become G♭. When you see a G with a flat next to the notehead, you would play the note that is a half-step lower than G, resulting in G♭, the black key immediately to the left of the G. 

The natural accidental (♮) can either raise or lower a note’s pitch because it cancels previous accidentals to return a note to its natural pitch. In the case of a pitch that has been altered within a measure, the natural sign will cancel the alteration of the pitch. Perhaps there is a measure with a G♯ on the first beat of the measure. If another G is notated in the measure, the G will remain a G♯ unless the natural sign is used on the following G in the same measure to return the G from G♯ to its natural state of G♮. Similarly, the natural sign is often used when a key signature indicates that certain notes are played with recurring accidentals. Eg. In the case of F Major, the B will always be played as B♭. However, if a B♮is introduced in the music, it returns the B♭ to its natural state of B♮.

The other two accidentals: double sharps and double flats are mainly related to minor keys or diminished chords and will raise the note by 2 half steps or a whole tone.

A double-sharp is an accidental for a note that has two sharps, meaning the original note is raised by two half-steps (also called semitones). The double-sharp symbol resembles a bold letter “x” and is placed before a notehead, similar to other accidentals.

The primary difference between a single sharp and a double sharp is the number of half-steps by which the natural note is altered. With a regular sharp, the natural note is raised one half-step, whereas, with a double-sharp, the natural note is raised two half-steps — meaning it is raised by a whole step. 

Eg. On the piano, single sharps usually point to black piano keys; double-sharps often point to piano naturals. For example, G# is a black key, but Gx is otherwise known as A-natural.

The double flat, as it’s name implies, is a flat x2. It’s essentially a mirror image of a double sharp; instead of raising a note by a whole step it lowers it by a whole step. A double flat is written simply as two flats side by side.