Contrapuntal motion


Audio: contrapuntal motion (0:06)

Contrapuntal motion
Figure: contrapuntal motion

Table: contrapuntal motion

contrapuntal motion sings first species counterpoint in the key of D dorian. The contrapuntal motion figure shows the interval between the parts in the score and identifies three different types of contrapuntal motion. The contrapuntal motion table lists the different types of contrapuntal motion:

  1. Contrary motion: one part ascends in pitch while the other part descends.
  2. Oblique motion: one part remains stationary while the other ascends or descends in pitch.
  3. Direct motion: both parts ascend or descend in pitch together:
    • Similar motion: the interval between the parts changes.
    • Parallel motion: the interval between the parts remains the same.

Contrapuntal motion focusses on the motion of parts relative to one other. In simple terms, contrapuntal motion is the motion of intervals. It is the most complex area of counterpoint because it simultaneously deals with the horizontal and vertical dimensions of harmony.

Contrapuntal motion is distinct from the motion of a contrapuntal melody. Contrapuntal motion is concerned with the motion of intervals, melodic motion is concerned with the motion of notes.

The preferred motion in counterpoint is contrary motion followed by oblique motion followed by similar motion followed by parallel motion. Contrary motion is the most preferred motion in counterpoint because it contrasts the parts. Parallel motion is the least preferred option because it does not provide contrast, both parts sound like one.

There is only one rule for contrapuntal motion:

  • Direct motion to a perfect consonance is prohibited.

This leads to the most famous prohibition in music: no parallel fifths. This prohibition applies to all perfect intervals: no parallel fifths, no parallel unisons and no parallel octaves.

The rule has some subtle consequences. First, it applies only to direct motion, not to oblique or contrary motion. In other words, it only applies to parts that move together up in pitch or down in pitch. Second, it applies to similar as well as parallel motion. For example, similar motion from a fifth to a third is OK but not the other way round because similar motion from a third to a fifth is direct motion to a perfect consonance. Third, parallel motion is not banned entirely, parallel thirds and parallel sixths are perfectly OK because they constitute direct motion to an imperfect consonance.

Contrary motion is the big new idea in counterpoint. Oblique motion is the same as drone harmony and parallel motion is the same as parallel harmony. Contrary motion is what makes counterpoint different.