music theory Music theory is the study of theoretical frameworks for understanding the practices and possibilities of music. ''The Oxford Companion to Music'' describes three interrelated uses of the term "music theory": The first is the "Elements of music, ...

, contrapuntal motion is the general movement of two or more melodic lines with respect to each other. In traditional

four-part harmony Four-part harmony is music written for four Human voice, voices, or for some other musical medium—four musical instruments or a single keyboard instrument, for example—for which the various musical parts can give a different note for each Cho ...

, it is important that lines maintain their independence, an effect which can be achieved by the judicious use of the four types of contrapuntal motion: parallel motion, similar motion, contrary motion, and oblique motion.Free-Ed.Ne
Traditional Harmony: Voice Motion
Retrieved 2011-09-15.

Parallel motion

Parallel motion is motion in the same direction, keeping the same interval between them. For example : : ParallelMotion

Parallel motion at an interval of a

perfect fifth In music theory, a perfect fifth is the Interval (music), musical interval corresponding to a pair of pitch (music), pitches with a frequency ratio of 3:2, or very nearly so. In classical music from Western culture, a fifth is the interval f ...

is known as parallel or consecutive fifths, and at an interval of an

octave In music, an octave (: eighth) or perfect octave (sometimes called the diapason) is an interval between two notes, one having twice the frequency of vibration of the other. The octave relationship is a natural phenomenon that has been referr ...

is known as parallel or consecutive octaves. Perfect intervals, i.e. the (perfect) unison, fifth and octave, are generally avoided in traditional

counterpoint In music theory, counterpoint is the relationship of two or more simultaneous musical lines (also called voices) that are harmonically dependent on each other, yet independent in rhythm and melodic contour. The term originates from the Latin ...

because they offer the lines so little independence from each other. In first-species counterpoint, it is recommended to limit parallel thirds or sixths to three consecutive uses of a given intervallic size. Chords between which all factors or voices move in parallel motion are called ''parallel chords''. This motion is called planing.

Similar motion

Similar motion is motion in the same direction, but with the interval between them changing. In other words, both lines move up, or both lines move down, but the interval between them is different in the first chord and the second chord. For example : : SimilarMotion

An important example of similar motion is in horn fifths.

Contrary motion

Contrary motion is motion in opposite directions. That is, when one of the lines moves up, the other line moves down (that is, in inversion). If the voices always move by the same intervals (in opposite directions) they are said to be in strict contrary motion. The following example shows two voices in contrary motion : : ContraryMotion

Contrary motion is important to maintain the independence of the melodic movement in contrapuntal writing as it creates the most independence between voices.

Oblique motion

Oblique motion is motion of one melodic line while the other remains at the same pitch. For example : : Oblique

If extended for enough time, the note that stays on the same pitch can be called a drone. Similar and oblique motion provide less independence than contrary motion, but more than parallel motion.

References

Bibliography