Lesson 12a: Double-Sharps & Double-Flats

As you likely already know, raising a letter-name by one semitone can be represented by placing a sharp in front of the note:

Similarly, lowering a letter name by one semitone can be represented by placing a flat in front of the note:

By placing a sharp in front of a note, we raise that note by one semitone. By placing a flat in front of a note, we lower that note by one semitone.

There are situations that arise in which we need to raise a note that is already sharp, thus creating a double-sharp. You will see that these situations occur most often in the building of certain minor scales. You will be constructing minor scales in Lesson 13, and so you will have to deal with double-sharps there.

A double-sharp sign looks like the letter "x": This note, called 'A-double-sharp,' is two semitones higher than 'A'. If you were to play it on your instrument, you would play a 'B'. Therefore, we say that 'A-double-sharp' and 'B' are enharmonic equivalents.

A double-flat literally looks like two flat signs side-by-side: This note, called 'A-double-flat', is two semitones lower than 'A'. If you were to play it on your instrument, you would play a 'G'. 'A-double-flat' and 'G' are said to be enharmonic equivalents. When two notes are ENHARMONICALLY EQUIVALENT, that means that they both produce the same pitch frequency.