Cadence

(Lat., cadere, fall; Ger. Kadenz). A generic term denoting the conclusion of a MELODY or MOVEMENT or the close or ending of a PHRASE, SECTION, or movement. The purpose of a cadence is to establish the terminal KEY of a musical composition.

A cadence consisting of a DOMINANT triad followed by the TONIC triad (V-I) is called an AUTHENTIC CADENCE. A cadence consisting of a SUBDOMINANT triad leading to a tonic triad (IV-I) is called a PLAGAL CADENCE (also called amen or oblique). In order to outline the tonality more fully, three chords are often used: the subdominant, the dominant, and the concluding tonic triad. This full authentic cadence (complete, perfect), includes all seven notes of the scale, thus outlining the key unambiguously.

Cadences that do not end on the tonic are an important feature of tonal music. The most common is the half cadence (imperfect), where the harmonic progression ends on the dominant chord, approached from any number of chords. An important type of irregular cadence is the deceptive cadence (evaded, interrupted), in which the dominant seventh chord leads into the SUBMEDIANT triad instead of the tonic triad, thus "deceiving" the expectations of the ear. In major keys, such a deceptive submediant is a minor triad (e.g., in C major, the A-minor chord), while in minor keys the submediant triad is major (e.g., in C minor, A-flat major).

In this Landini cadence, named after the ARS NOVA composer FRANCESCO LANDINI, the leading tone in the melody is diverted to the submediant, a degree below, before resolving into the tonic (7-6-8) . To modern ears, this melodic twist creates a momentary impression of a piagai cadence.

Cadences can be endlessly ornamented, and the final resolution to the tonic chord endlessly delayed, creating harmonic suspense. The concluding tonic chord may then be repeated several times, in varying rhythmic figures and harmonic positions, so that the melody may traverse through the third or the fifth note of the tonic triad before arriving at the fundamental.

There can be numerous repetitions of the tonic chord at the end of a composition. In the resonant C-major coda of Ludwig van Beethoven's Fifth Symphony, the tonic chord is repeated, after alternating with the dominant triad, 15 times. At the end of his Eighth Symphony, it is repeated 24 times.

In modern compositions cadences are apt to be abrupt. SERGEI PROKOFIEV'S March from his Love for 3 Oranges ends in a single C-major chord preceded by the briefest appearance of the dominant. While in CLASSICAL and ROMANTIC music the final chord cannot possibly consist of more than three notes of the tonic harmony, 20th-century composers have introduced a type of a cadence in which the tonic triad is supplemented, so that the C-major triad blossoms out into a chord of C-E-G-A , C-E-G-B , or C-G-E-A-D , or other combinations of those ingredients, comprising every degree of the scale except the subdominant. JAZZ musicians popularized harmonies with "added notes," culminating in final chords with added sixths, sevenths (natural or flatted), ninths, 11ths (usually sharped), and 13ths. These chords are all technically classified as DISSONANCES, but they all sound more satisfying in a jazz context than undiluted, old-fashioned tonic harmony.