In music, counterpoint is the relationship between voices that are harmonically interdependent (polyphony) yet independent in rhythm and contour. It has been most commonly identified in the European classical tradition, strongly developing during the Renaissance and in much of the common practice period, especially in the Baroque. The term originates from the Latin punctus contra punctum meaning "point against point”.
GENERAL PRINCIPLES
Counterpoint generally involves musical lines with strongly independent identities. Counterpoint has been used to designate a voice or even an entire composition. In each era, contrapuntally organized music writing has been subject to rules—sometimes strict ones. Chords are the simultaneous soundings of notes; whereas harmonic, "vertical" features are considered secondary and almost incidental when counterpoint is the predominant textural element.[citation needed] Counterpoint focuses on melodic interaction—only secondarily on the harmonies produced by that interaction. In the words of John Rahn:
"It is hard to write a beautiful song. It is harder to write several individually beautiful songs that, when sung simultaneously, sound as a more beautiful polyphonic whole. The internal structures that create each of the voices separately must contribute to the emergent structure of the polyphony, which in turn must reinforce and comment on the structures of the individual voices. The way that is accomplished in detail is ... 'counterpoint'."
SPECIES COUNTERPOINT
Species counterpoint generally offers less freedom to the composer than other types of counterpoint and therefore is called a "strict" counterpoint. Species counterpoint was developed as a pedagogical tool in which students progress through several "species" of increasing complexity, with a very simple part that remains constant known as the cantus firmus (Latin for "fixed melody"). The student gradually attains the ability to write free counterpoint (that is, less rigorously constrained counterpoint, usually without a cantus firmus) according to the given rules at the time.[4] The idea is at least as old as 1532, when Giovanni Maria Lanfranco described a similar concept in his Scintille di musica (Brescia, 1533). The 16th-century Venetian theorist Zarlino elaborated on the idea in his influential Le institutioni harmoniche, and it was first presented in a codified form in 1619 by Lodovico Zacconi in his Prattica di musica. Zacconi, unlike later theorists, included a few extra contrapuntal techniques, such as invertible counterpoint.
The following rules apply to melodic writing in each species, for each part:
1 The final must be approached by step. If the final is approached from below, then the leading tone must be raised in a minor key (Dorian, Hypodorian, Aeolian, Hypoaeolian), but not in Phrygian or Hypophrygian mode. Thus, in the Dorian mode on D, a C♯ is necessary at the cadence.
2 Permitted melodic intervals are the perfect fourth, fifth, and octave, as well as the major and minor second, major and minor third, and ascending minor sixth. The ascending minor sixth must be immediately followed by motion downwards.
3 If writing two skips in the same direction—something that must be only rarely done—the second must be smaller than the first, and the interval between the first and the third note may not be dissonant. The three notes should be from the same triad; if this is impossible, they should not outline more than one octave. In general, do not write more than two skips in the same direction.
4 If writing a skip in one direction, it is best to proceed after the skip with motion in the other direction.
5 The interval of a tritone in three notes should be avoided (for example, an ascending melodic motion F–A–B♮)[citation needed] as is the interval of a seventh in three notes.
6 There must be a climax or high point in the line countering the cantus firmus. This usually occurs somewhere in the middle of exercise and must occur on a strong beat.
7 An outlining of a seventh is avoided within a single line moving in the same direction.
And, in all species, the following rules govern the combination of the parts:
1 The counterpoint must begin and end on a perfect consonance.
2 Contrary motion should predominate.
3 Perfect consonances must be approached by oblique or contrary motion.
4 Imperfect consonances may be approached by any type of motion.
5 The interval of a tenth should not be exceeded between two adjacent parts unless by necessity.
6 Build from the bass, upward.
CONTRAPUNTAL DERIVATIONS
Since the Renaissance period in European music, much contrapuntal music has been written in imitative counterpoint. In imitative counterpoint, two or more voices enter at different times, and (especially when entering) each voice repeats some version of the same melodic element. The fantasia, the ricercar, and later, the canon and fugue (the contrapuntal form par excellence) all feature imitative counterpoint, which also frequently appears in choral works such as motets and madrigals. Imitative counterpoint spawned a number of devices that composers use to give their works both mathematical rigor and expressive range. These devices include:
Melodic inversion
The inverse of a given fragment of melody is the fragment turned upside down—so if the original fragment has a rising major third (see interval), the inverted fragment has a falling major (or perhaps minor) third, etc. (Compare, in twelve tone technique, the inversion of the tone row, which is the so-called prime series turned upside down.) (Note: in invertible counterpoint, including double and triple counterpoint, the term inversion is used in a different sense altogether. At least one pair of parts is switched, so that the one that was higher becomes lower. See Inversion in counterpoint; it is not a kind of imitation, but a rearrangement of the parts.)
Retrograde
Whereby an imitative voice sounds the melody backwards in relation the leading voice.
Retrograde inversion
Where the imitative voice sounds the melody backwards and upside-down at once.
Augmentation
When in one of the parts in imitative counterpoint the note values are extended in duration compared to the rate at which they were sounded when introduced.
Diminution
When in one of the parts in imitative counterpoint the note values are reduced in duration compared to the rate at which they were sounded when introduced.