Counterpoint is a musical device where two or more melodic phrases occur simultaneously. The term comes from the Latin punctus contra punctum (note against note). A note moves against another note when the interval between those two notes either grows or shrinks. By definition, chords occur when multiple notes sound simultaneously; however, this effect is considered incidental. Counterpoint focuses on melodic interaction rather than harmonic effect. The composer Johann Sebastian Bach frequently wrote music using counterpoint and systematically explored the technique in the Art of Fugue.
Generally, such music created from the Baroque period on is described as counterpoint, while music created prior to Baroque times is called polyphony. Hence, the composer Josquin Des Prez wrote polyphonic music.
Counterpoint is one of the most essential means, in musical composition, for the generation of musical ironies; a melodic fragment, heard alone, may make a particular impression, but when heard simultaneously with other melodic ideas, or combined in unexpected ways with itself, as in canon or fugue, surprising new facets of meaning are revealed. This is a means for bringing about development of a musical idea, revealing it to the listener as conceptually more profound than a merely pleasing melody.
In first species counterpoint, a note simply works against another note. The two notes are played simultaneously, and move against each other, also simultaneously. The species is said to be expanded if one of the notes is broken up (but repeated).
In second species counterpoint, two notes work against a longer note. The species is said to be expanded if one of the shorter notes varies in length from the other.
In third species counterpoint, four notes move against a longer note. As with second species, it is expanded if one of the shorter notes varies in length from another.
In fourth species counterpoint, a note is held while other notes move against it, creating a dissonance, followed by the holding note changing to create a subsequent consonance as the changing note holds. Fourth species counterpoint is said to be expanded when the notes vary in length from each other. The technique requires holding a note across the beat, creating syncopation.
In fifth species counterpoint, sometimes called florid counterpoint, the other four species of counterpoint are combined within the melody.
It is a common misconception that counterpoint is defined by these five species, and therefore anything that does not follow the strict rules of the five species is not counterpoint. This is not true; although much contrapuntal music of the common practice period indeed adheres to the rules, there are exceptions. Fux's book and its concept of "species" was purely a method of teaching counterpoint, not a definitive set of rules for it.
Since the Renaissance period in European music, most music which is considered contrapuntal has been written in imitative counterpoint. In imitative counterpoint, two or more voices enter at different times, and when entering each voice repeats the same musical phrase. The fantasia, the ricercar, and later, the fugue (the contrapuntal form par excellence) all feature imitative counterpoint, which also frequently appears in choral works such as motets and madrigals. Imitative counterpoint has spawned a number of devices that composers have turned to in order to give their works both mathematical rigor and expressive range. Some of these devices include:
- Inversion: The inverse of a given melody is the melody turned upside-down—so if the original melody has a rising major third (see interval), the inverted melody has a falling major third. Similarly, in the twelve tone technique, the inversion of the tone row is the so-called prime series turned upside-down. When applied to counterpoint, a contrapuntal inversion of two melodies simultaneously being played by two voices is the switching of the melodies between voices, so that the upper-voice melody is now played in the lower voice, and vice versa
- Retrograde refers to the contrapuntal device whereby an imitative voice plays backwards in relation to the original.
- Retrograde inversion is where the imitative voice is both backwards and upside down.
- Augmentation is when one of the lines in imitative counterpoint is extended in duration compared to the rate at which it was played when introduced, i.e. the note values are longer.
- Diminution is when one of the lines in imitative counterpoint is speeded up in relation to how it was originally heard, i.e. the note values are shorter.
Dissonant counterpoint was first theororized by Charles Seeger as "at first purely a school-room discipline," consisting of species counterpoint but with all the traditional rules reversed. First species counterpoint is required to be all dissonances, establishing "dissonance, rather than consonance, as the rule", and consonances are "resolved" through a skip, not step. He wrote that "the effect of this discipline" was "one of purification." Other aspects of composition, such as rhythm, could be "dissonated" by applying the same principle. (Charles Seeger, "On Dissonant Counterpoint," Modern Music 7, no. 4 (June-July 1930): 25-26)
Seeger was not the first to employ dissonant counterpoint, but was the first to theorize and promote it. Other composers who have used dissonant counterpoint, if not in the exact manner prescribed by Charles Seeger, include Ruth Crawford-Seeger, Carl Ruggles, Dane Rudhyar, and Arnold Schoenberg.
- On Dissonant Counterpoint by David Nicholls
- Dane Rudhyar's Vision of American Dissonance by Carol J. Oja
- Dissonant counterpoint examples and definition
- De-Mystifying Tonal Counterpoint or How to Overcome Your Fear of Composing Counterpoint Exercises by Christopher Dylan Bailey, composer at Columbia