Species counterpoint is a step-by-step method for learning to write melodies and to combine them.

While the "rules" involved are somewhat linked to music in the 16th century, the idea really is to train basic skills, independent of a specific repertoire or style.

This chapter recaps some key concepts we met in the Fundamentals section and introduces some basic "rules" that will be relevant for each of the following chapters, including some terms for:

Consonance and dissonance:

Perfect consonances: perfect unisons, fifths, and octaves

Imperfect consonances: major and minor thirds and sixths

Dissonances: all seconds, sevenths, and diminished and augmented intervals

Types of two-part motion:

Contrary: the two parts move in opposite directions (one up, the other down

Similar: the two parts move in the same direction (both up or both down)

Parallel: the two parts move in the same direction (both up or both down) by the same distance, such that the starting and ending intervals are of the same type (e.g., parallel thirds)

Oblique: one part moves, the other stays on the same pitch

We begin with a specific method called species counterpoint. The term "species" is probably most familiar as a way of categorizing animals, but it is also used in a wider sense to refer to any system of grouping similar elements. Here, the species are types of exercises that are done in a particular order, introducing one or two new musical “problems” at each stage. (So no, we won't have any elephants or monkeys singing polyphony, sorry!)

While there are many variants on this approach, the chapters here are closely based on Johann Joseph Fux's Gradus ad Parnassum (Steps to Parnassus, 1725)). Many composers from the 18th to the 21st centuries have used this method, or some variation on it. In the first part of Gradus ad Parnassum, Fux works through five species for combining two voices, which will be the focus of our next five chapters. The “Gradus ad Parnassum” Exercises chapter provides all of the exercises from Gradus ad Parnassum in an editable format so you can try this yourself.

Before getting into the five species, we begin in this chapter by introducing principles that apply to writing lines in any species. These principles build on concepts from the Fundamentals section, such as intervals and scale degrees.

Consonance and dissonance

Consonance and dissonance was introduced in a previous chapter, but in counterpoint, we further distinguish between:

Perfect consonances (perfect unisons, fifths, and octaves)

Imperfect consonances (major and minor thirds and sixths)

Dissonances (all seconds, sevenths, and diminished and augmented intervals)

These categories are summarized in Example 1 below.

[](https://viva.pressbooks.pub/app/uploads/sites/12/2019/05/Consonance.png) Example 1. Perfect consonances, imperfect consonances, and dissonances.

The elusive perfect fourth

As in many theories of tonal music, the perfect fourth has a special status in species counterpoint that depends on where it appears in the texture. Basically, the interval of a perfect fourth is dissonant when it involves the lowest voice in the texture, but it is consonant when it occurs between two upper voices.

As this survey of species counterpoint will only cover two-voice textures, all fourths will involve the lowest part and therefore be classed as dissonant. Later chapters in this section will address the resolution of this dissonance, and the Strengthening Endings with Cadential ^6_4 and ^6_4 Chords as Forms of Prolongation chapters in the Diatonic Harmony section discuss this topic further.

Types of motion

Species counterpoint also concerns the motion between melodic lines (demonstrated in Example 2):

Contrary: the two parts move in opposite directions (one up, the other down)

Similar: the two parts move in the same direction (both up or both down)

Parallel: the two parts move in the same direction (both up or both down) by the same distance, such that the starting and ending intervals are of the same type (e.g., parallel thirds)

Oblique: one part moves, the other stays on the same pitch

Example 2. Examples of different types of motion.

Composing a Cantus Firmus

Exercises in strict voice leading, or species counterpoint, begin with a single well-formed musical line called the cantus firmus ("fixed voice" or "fixed melody"; plural "cantus firmi"). Cantus firmus composition gives us the opportunity to engage the following fundamental musical traits:

smoothness

independence and integrity of melodic lines

variety

motion (toward a goal)

Example 3 contains all the cantus firmi that Fux uses throughout Gradus at Parnassum: one for each mode, presented here in the upper and lower of two parts. Apart from using this to review the type of cantus firmi Fux composed, you can use this to practice any of the species, on any of the modes, and in both the upper and lower parts.

Example 3. Cantus firmi from Gradus ad Parnassum.

Notice how in each case, the general musical characteristics of smoothness, melodic integrity, variety, and motion toward a goal are worked out in specific characteristics. The following characteristics are typical of all well-formed cantus firmi:

length of about 8–16 notes

arhythmic (all whole notes; no long or short notes)

begin and end on do (\hat1)

approach final tonic by step: usual