Pedal point
Pedal point (also pedal tone, organ point, or just pedal) is a musical term describing any sustained or repeated note, usually in the bass, with changing harmonies in the other voices. The technique is often found near the end of a fugue or other polyphonic composition. Usually a pedal point is either the tonic or the dominant note, typically with some of the harmonies played above the pedal being dissonant with the pedal note. The pedal tone is considered a chord tone in the original harmony then a nonchord tone of the dissonant harmony and a chord tone when the harmony resolves. A dissonant pedal point may go against all harmonies present during its duration, being almost more like an added tone than a nonchord tone, or pedal points may serve as atonal pitch centers.
The term comes from the organ for its ability to sustain a note indefinitely and the tendency for such notes to be played on a pedal division.
A double pedal is two pedal tones played simultaneously.
An inverted pedal is a pedal that is not in the bass (and often is the highest part.) Mozart included numerous inverted pedals in his works, particularly in the solo parts of his concertos.
Pedal points are somewhat problematic on the harpsichord or piano, which have only limited sustain. Often the pedal note is simply repeated at intervals. They can also be realized with a trill, particularly frequent with inverted pedals.
A drone differs from a pedal point in degree or quality. A pedal point may be a nonchord tone and thus required to resolve unlike a drone, or a pedal point may simply be a shorter drone, a drone being a longer pedal point.
The term pedal point also has a mathematical meaning: it is the point with respect to which a pedal curve is drawn.
