Key (music)

In traditional Western music, the key is the tonal center of a composition. The choice of key determines which of the other notes in the scale will be considered "natural".

The Western scale divides the octave into twelve notes (including the octave, at double the frequency of the lowest note). Any given key uses eight of these, or seven plus the octave, from which the composer can construct melodies and harmonies. Since many times the judicious use of the other four notes will make the music more compelling, we have notation devices to indicate when they are used instead of their natural counterparts. A piece of music will also often shift key at various times. This is usually done by moving to a closely related key, that is, one that is only one or two notes different than the key leading to it. An easy way to find which keys are related in this way is to follow the circle of fifths.

The notes used in the key of C major (corresponding to the white notes on the piano) are C, D, E, F, G, A, B and C. When sung or played, these are the familiar do, re, mi, fa, so, la ti, and do.

Some modern composers have blatantly violated these "rules", writing "atonal" or "twelve tone" music, to achieve a different effect.

Many styles, or genres, of music are quite recognizable by the type of key structure they employ.

Also see

Chord (music)