The sharp symbol (#) raises the pitch of a note by a semitone (or “half step”). D# is one semitone higher than D, and F# is one semitone higher than F.
Double sharps raise the pitch of a note by two semitones (or a “whole step”), and the double sharp is printed as a sort of fancy cross, like this:
When you write them by hand, you can just write a normal cross, like an X.
This note is G double sharp:
In the same way, a double flat lowers the pitch of a note by two semitones (a whole step). There is no special symbol for a double flat, we just write two flat signs close to each other, like this:
This note is E double flat:
Why do we need double sharps and flats?
Double sharps are very common. We need them when we write music in some minor keys, when those keys contain a lot of sharps. You’ll learn more about this in the lesson on scales.
Double flats are much less common – they are usually used when a piece of music is modulating (in the process of changing key), or in chromatic scale passages (chromatic scales are in a later lesson).
Cancelling Double Sharps and Flats
Double flats and sharps affect any subsequent notes in the same bar of the same pitch, just like single flats and sharps. But let’s say you need a D double sharp followed by a D sharp. There are two ways you can notate this:
- You can write a single sharp or flat on the D#, or
- you can add a natural sign before the sharp/flat on the D#
Both of these methods are acceptable:
Some people consider it to be a bit “old fashioned” or “untidy” to use the second method to cancel an accidental. You will probably see it in lots of printed music, however.
If you need to write a natural note after a double sharp/flat, simply write the note with a single natural sign:
You don’t need to write two natural signs, one is enough.
An “enharmonic equivalent” is a note which sounds the same as another note with a different name.
Let’s start with an easy example- F sharp. We know that F sharp is one semitone (half step) higher than F (natural). But we also know that it’s one semitone lower than G natural, so we could also call the note G flat. An enharmonic equivalent is simply another way to “spell” the same note. F sharp and G flat are “enharmonic equivalents” because they sound the same, but have different names.
Some common enharmonic equivalents are C#/Db, D#/Eb, G#/Ab and A#/Bb. These are the black notes on a piano keyboard.
Slightly trickier, these are white notes on the piano: E/Fb, E#/F, B/Cb and B#/C.
All the notes with double sharps and flats also have enharmonic equivalents: C##/D, D##/E, F##/G, G##/A and A##/B, and for the flats, C/Dbb, D/Ebb, F/Gbb, G/Abb and A/Bbb. The enharmonic equivalents of all the double sharp/flat notes are always natural notes.
Remember that when you write scales, you can only use each letter name once (except for the tonic). This means that you have to be careful to choose the correct enharmonic equivalent. For example, in the scale of G# minor, the 7th degree of the scale is F##. An enharmonic equivalent of F## is G natural, but you cannot write G natural in a G# minor scale, because the letter name is already used for the 1st degree of the scale. (See “Scales” for more on this!)
In the Exam
In the grade four exam, you might be asked to find the enharmonic equivalent of one or two notes. It’s usually easier to do this if you can imagine a piano keyboard. If you find it hard to imagine a keyboard in your head, sketch an octave of a mini keyboard out on some scrap paper.
Double Sharps/Flats & Enharmonics Exercises
Hover your mouse over the questions (tap on mobiles) to reveal the answers.
1. Name each of these notes:
2. On the staves below, write the notes stated, as given in the first example. Write the notes as minims (half-notes) and use ledger lines if necessary.
3. Write an enharmonic equivalent next to each of the following notes. (Alternative answers may also be correct in some cases).
4. For each pair of notes, say whether they are enharmonic equivalents or not.