plagal cadence

In Western musical theory, a harmonic cadence (Latin cadentia, "a falling") is a progression of (at least) two chords that concludes a phrase, section, or piece of music.^[1] A rhythmic cadence is a characteristic rhythmic pattern indicating the end of a phrase.^[2] Cadences give phrases a distinctive ending, which can, for example, indicate to the listener whether the piece is to be continued or concluded. An analogy may be made with punctuation,^[3] with some weaker cadences acting as commas, indicating a pause or momentary rest, while a stronger cadence will then act as the period, indicating the end of the phrase or musical sentence. A cadence is labeled more or less "weak" or "strong" depending on the sense of finality it creates. While cadences are usually classified by specific chord or melodic progressions, the use of such progressions does not necessarily constitute a cadence—there must be a sense of closure, as at the end of a phrase. Harmonic rhythm plays an important part in determining where a cadence occurs.

Edward Lowinsky thought that the cadence was the "cradle of tonality."^[4]

Classification of cadences in common practice tonality

In music of the common practice period, cadences are divided into four types according to their harmonic progression: authentic, plagal, half, and deceptive. Typically, phrases end on authentic or half cadences, and the terms plagal and deceptive refer to motion that avoids or follows a phrase-ending cadence. Each cadence can be described using the Roman numeral system of naming chords:

• Authentic (also closed or standard) cadence: V to I (or IV - V - I). The phrase perfect cadence is sometimes used as a synonym for authentic cadence, but can also have a more precise meaning depending on the chord voicing:
  • Perfect authentic cadence (PAC): The chords are in root position; that is, the roots of both chords are in the bass, and the tonic (the same pitch as root of the final chord) is in the highest voice of the final chord. A PAC is a progression from V to I in major keys, and V to i in minor keys. This is generally the strongest type of cadence.
  • Imperfect authentic cadence (IAC), best divided into three separate categories:
    • 1. Root position IAC: similar to a PAC, but the highest voice is not the tonic ("do" or the root of the tonic chord).
    • 2. Inverted IAC: similar to a PAC, but one or both chords must be inverted.
    • 3. Leading tone IAC: the V chord is replaced with the vii^o/subV chord (but the cadence still ends on I).
• Half (or open, or imperfect) cadence: any cadence ending on V, whether preceded by V of V, ii, IV, or I, or any other chord. Because it sounds incomplete or "suspended", half cadence is considered a weak cadence.
  • Phrygian half cadence: a half cadence from IV⁶ to V in minor, so named because the semitonal motion in the lower part (flat sixth degree to fifth degree) resembles the semitone heard in the II - I of the ancient (fifteenth century) cadence in the Phrygian mode.
• Plagal cadence: IV to I, also known as the "Amen Cadence" because of its frequent setting to the text "Amen" in hymns. However, William Caplin disputes the existence of plagal cadences: "An examination of such a cadence rarely exists...In as much as the progression IV-I cannot confirm a tonality (it lacks any leading tone resolution), it cannot articulate formal closure. Rather, this progression is normally part of a tonic prolongation serving a variety of formal functions - not, however a cadential one. Most examples of plagal cadences given in textbooks actually represent a postcadential codetta function: that is, the IV-I progression follows an authentic cadence but does not itself create genuine cadential closure."^[5]
• Deceptive (or interrupted, or surprise) cadence: V to any chord other than I (typically ii, IV6, iv6, vi or VI). This is considered a weak cadence because of the "hanging" (suspended) feel it invokes. One of the most famous examples is in the coda of the Passacaglia and Fugue in C minor, BWV 582 by Johann Sebastian Bach: Bach repeats a chord sequence ending with V over and over, leading the listener to expect resolution to I—only to be thrown off completely with a fermata on a striking, D-flat major chord in first inversion (bII–the Neapolitan chord). Following a pregnant pause, the "real" ending commences. At the beginning of the final movement of Template:Gustav Mahler's Template:9th Symphony, the listener hears a string of many deceptive cadences progressing from V to IV6.

Rhythmic classifications

Cadences can also be classified by their rhythmic position. A "masculine cadence" occurs on a strong position, typically the downbeat of a measure. A "feminine cadence" occurs in a metrically weak position, for instance, after a long appoggiatura (see also feminine ending). Masculine cadences are considered stronger and are generally of greater structural significance. Susan McClary has written extensively on the gender characteristics of music in her book Feminine Endings.^[6] The Society for Music Theory endorses the terms "metrically accented" and "metrically unaccented cadence" in their Guidelines for Nonsexist Language.^[7]

Likewise, cadences can be classified as either transient (a pause, like a comma in a sentence, which implies that the piece will go on after a brief lift in the voice) or terminal (more conclusive, like the full stop or other terminal punctuation, which implies that, at least for the time being, we are done). Most transient cadences are half cadences (which stop momentarily on a dominant chord), though IAC or deceptive cadences are also usually transient, as well as Phrygian cadences. Terminal cadences are usually PAC or sometimes plagal ("Amen") cadences.

Cadences in medieval polyphony

Medieval cadences are based upon dyads rather than chords. The first theoretical mention of cadences comes from Guido of Arezzo's description of the occursus in his Micrologus, which is the term he gives to the end of a phrase of two-part polyphony where the two lines converge to a unison.

A clausula is a dyadic or intervallic, rather than chordal or harmonic, cadence. It requires at least two voices in contrary motion. According to Carl Dahlhaus, "as late at the 13th century the half step was experienced as a problematic interval not easily understood, as the irrational remainder between the perfect fourth and the ditone:

^[8]

In a melodic half step, no "tendency was perceived of the lower tone toward the upper, or of the upper toward the lower. The second tone was not taken to be the 'goal' of the first. Instead, the half step was avoided in clausulas because it lacked clarity as an interval." Beginning in the 13th century cadences begin to require motion in one voice by half step and the other a whole step in contrary motion. In the 14th century, an ornamentation of this with an escape tone became known as the Landini cadence, after the composer who used them prodigiously.

Classical cadential trill

In the Classical period, composers often drew out the authentic cadences at the ends of sections; the cadence's dominant chord might take up a measure or two, especially if it contained the resolution of a suspension remaining from the chord preceding the dominant. During these two measures, the solo instrument (in a concerto) often played a trill on the supertonic (the fifth of the dominant chord); although supertonic and subtonic trills had been common in the Baroque era, they usually lasted only a half measure (e.g., the subtonic trill in the final cadence from Bach's "Wachet auf, ruft uns die Stimme").^[9] Extended cadential trills were by far most frequent in Mozart's music, and although they were also found in early Romantic music, their use was restricted chiefly to piano concerti (and to a lesser extent, violin concerti) because they were most easily played and most effective on the piano and violin; the cadential trill and resolution would be generally followed by an orchestral coda. Because the music generally became louder and more dramatic leading up to it, a cadence was used for climactic effect, and was often embellished by Romantic composers. Later on in the Romantic era, however, other dramatic virtuosic movements were often used to close sections instead.

Notes

See also

• Caribbean Music
• Kadans
• Andalusian cadence
• English cadence
• Backdoor progression
• Cadenza
• Picardy third
• ii-V-I turnaround