The Latin word alterare means to change. In musical science alteration is called the rise and fall of sound, in which the name is not changed.
Any sound can be increased by semitone or tone, can be lowered a semitone or tone. In music this is indicated by the so-called signs of alteration. Here they are:
- sharp - increase of a semitone;
- double-sharp - increase of a tone;
- flat - lowering of a semitone;
- double flat - down a whole tone.
If after arteriovenous sound should sound natural, write a sign of failure - Bekar (or, if necessary, double-Bekar
If arteriovenus sound appears in a piece of music by accident once (for example, d-sharp or f-sharp in C major, the duet), the sign of alteration is placed directly in front of him and is only considered up to the end of the stroke, in which, and only to the octave in which you specified. But when in the same step further should sound alterirovannye sound, before he is given a sign of failure - Bekar.
At first glance it may seem that the signs of alteration is the legend of the black keys of the piano keyboard, while the white keys have their own names. But things are not so simple. Signs of alteration indicate no keys, and sounds. And a black key between the white FA and Sol, depending on the tone in which executable written your play can be and f-sharp and g-flat. As in any work (usually more complex, not intended for beginning musicians) will occur, for example, up-double-sharp or g-double-flat, which is on the piano keyboard will be equal, respectively, to the notes d and f, but in the performed play, in the sense of deployment melodies or harmonic logic patterns, will be "double-sharp or double-flat".