Key Signatures, Sharps and Flats

Sharp	Flat	Double Sharp	Double Flat	Natural

Shaps and flats are called accidentals and change the pitch of a note by half a tone - a whole tone being the difference between two adjacent notes. What do we mean by this? - Doh-Rey-Me-Fah-Soh-La-Te-Doh are all tones but a composer may want to use notes between these - to use half-tones or semitones.

These symbols appear just to the left of the note on which they have their influence.

Example: Sharps and Baa Baa Black Sheep

This is what Baa Baa Black Sheep should soundlike (click on the music to hear it). You can see that notes in bars 2, 3, 6 and 8 have sharps next to them - this means that the pitch of these notes is raised by a semitone.

Note - rather than write a sharp against all of the notes of the same pitch in a bar we write it against the first one and assume that all the others following it are the same. In this example the first three notes (all the same pitch) are "sharped" but we only need to write it against the first one. If this happens again in the next bar we need to write a new sharp against the first one we want "sharped".

To show the importance of sharps and flats I've taken them out of the one below (click on it to hear the horrific results) - you will notice that the notes which had the sharps before are not quite as high as they should be - although this doesn't sound like a big deal it can have astounding effects.

The same goes for flats but these take the pitch of the note down a semitone rather than up like the sharps do.

Naturals

If we don't want all the notes in a bar to be under the influence of a sharp or a flat then we must "cancel" the sharp or the flat by sticking in the natural.

In other words a sharp/flat in a bar will turn on the semitone up/down for all the notes of that pitch in a bar while a natural will turn off that effect. You can turn the effect on again later in the bar by sticking in another sharp or flat again.

Double Sharps and Double Flats

These are much rarer than ordinary sharps and flats and change the pitch of the notes they are next to by two semitones up/down.

Key Signatures

things can get very complicated very quickly if you have to put sharps and flats all over the place - a way to simplify things is to put in a key signature.

For example:

You can see that there are no sharps or flats in front of these notes - just as in the horrible, "wrong" version of Baa Baa Black Sheep above. The difference is that it has a key signature at the left hand side. This key signature (called D major by the way) has a sharp on the top line of the staff (F) and on the second space down (C) - this means that, in all of this music, all of the Cs and all of the Fs automatically have a sharp attached to them without having to write one each time we stick in a C or an F. If we don't want a sharp on a C or F at any point in the piece we will need a natural in there.

Note - One thing we must not forget is the octaves! The sharps apply to the line they are on (red lines) but also to the octaves above and below (yellow)