Plagal mode
Encyclopedia
A Plagal mode may mean different church chanting modes, depending on the context.
πλάγιος 'oblique, sideways, athwart') is a musical mode
, which is one of four Gregorian mode
s whose range includes the octave from the fourth below the tonic, or final, to the fifth above. The plagal modes are the even-numbered modes, 2, 4, 6 and 8, and each takes its name from the corresponding odd-numbered ("authentic") mode, with the addition of the prefix "hypo-": Hypodorian, Hypophrygian, Hypolydian, and Hypomixolydian.Harold S. Powers, "Plagal mode", in Grove Music Online (Oxford Music Online, accessed February 2009) (Subscription access).
The earliest definition of the term is found in Hucbald's treatise De harmonica (ca. 880), who specifies the range as running from the fourth below the final to the fifth above. Later writers extend this general rule to include the sixth above the final and the Fifth below, except for the Hypolydian mode
, which would have a diminished fifth below the final and so the 4th below, C, remained the lower limit. In addition to the range, the tenor (cofinal, or dominant, corresponding to the "reciting tone
" of the psalm tones) differs. In the plagal modes, the tenor is a third lower than the tenor of the corresponding authentic mode, except in mode 8 (hypomixolydian), where it is raised to a 4th above the finalis (a second below the tenor of the authentic mode, 7) in order to avoid the "unstable" degree B/B♭ (in the authentic mode 3, the tenor is similarly raised to the 6th above the finalis, and the tenor of plagal mode 4—hypophrygian—is therefore also a fourth above the finalis).
) the word "Plagal" ("plagios") refers to the four lower-lying echoi, or modes. Thus Plagal 1st mode (also known as "Tone 5" in Russian naming system) represents a somewhat more developed and widened in range version of the 1st mode. Plagal 2nd mode ("Tone 6" in Russian system) stays in a similar relation to 2nd mode, and Plagal 4th mode - respectively to the 4th mode. Though there is no "Plagal 3d mode," the mode that one would expect standing there ("Tone 7") is called Grave tone. .
In Western Practice
A plagal mode (from GreekGreek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
πλάγιος 'oblique, sideways, athwart') is a musical mode
Musical mode
In the theory of Western music since the ninth century, mode generally refers to a type of scale. This usage, still the most common in recent years, reflects a tradition dating to the middle ages, itself inspired by the theory of ancient Greek music.The word encompasses several additional...
, which is one of four Gregorian mode
Gregorian mode
A Gregorian mode is one of the eight systems of pitch organization used to describe Gregorian chant.The name of Pope Gregory I was attached to the variety of chant that was to become the dominant variety in medieval western and central Europe by the Frankish cantors reworking Roman ecclesiastical...
s whose range includes the octave from the fourth below the tonic, or final, to the fifth above. The plagal modes are the even-numbered modes, 2, 4, 6 and 8, and each takes its name from the corresponding odd-numbered ("authentic") mode, with the addition of the prefix "hypo-": Hypodorian, Hypophrygian, Hypolydian, and Hypomixolydian.Harold S. Powers, "Plagal mode", in Grove Music Online (Oxford Music Online, accessed February 2009) (Subscription access).
The earliest definition of the term is found in Hucbald's treatise De harmonica (ca. 880), who specifies the range as running from the fourth below the final to the fifth above. Later writers extend this general rule to include the sixth above the final and the Fifth below, except for the Hypolydian mode
Hypolydian mode
The Hypolydian mode, literally meaning "below Lydian", is the common name for the sixth of the eight medieval church modes . The name is taken from Ptolemy of Alexandria's term for one of his seven tonoi, or transposition keys...
, which would have a diminished fifth below the final and so the 4th below, C, remained the lower limit. In addition to the range, the tenor (cofinal, or dominant, corresponding to the "reciting tone
Reciting tone
In chant, a reciting tone is a repeated musical pitch around which the other pitches of the chant gravitate, or by extension, the entire melodic formula that centers on one or two such pitches. In Gregorian chant, reciting tones are used for a number of contexts, including the chanting of psalm...
" of the psalm tones) differs. In the plagal modes, the tenor is a third lower than the tenor of the corresponding authentic mode, except in mode 8 (hypomixolydian), where it is raised to a 4th above the finalis (a second below the tenor of the authentic mode, 7) in order to avoid the "unstable" degree B/B♭ (in the authentic mode 3, the tenor is similarly raised to the 6th above the finalis, and the tenor of plagal mode 4—hypophrygian—is therefore also a fourth above the finalis).
In Byzantine Practice
In Byzantine modal theory (OctoechosOctoechos
Oktōēchos is the name of the eight mode system used for the composition of religious chant in Syrian, Coptic, Byzantine, Armenian, Latin and Slavic churches since the middle ages...
) the word "Plagal" ("plagios") refers to the four lower-lying echoi, or modes. Thus Plagal 1st mode (also known as "Tone 5" in Russian naming system) represents a somewhat more developed and widened in range version of the 1st mode. Plagal 2nd mode ("Tone 6" in Russian system) stays in a similar relation to 2nd mode, and Plagal 4th mode - respectively to the 4th mode. Though there is no "Plagal 3d mode," the mode that one would expect standing there ("Tone 7") is called Grave tone. .