The following guidelines affirm some basic characteristics of complete melodic phrases in Western chamber music and sacred music in the 16th-through-18th centuries. Zarlino (Istitutioni Harmoniche: 1558), Reicha (Treatise on Melody: 1813), and Kennan (Counterpoint: 1999).
1. Use a good mixture of skips, steps, and leaps. Students of counterpoint tend to use stepwise motion as a fall-back plan when writing multi-voice textures, because it seems to guarantee coherence or deliberateness. In fact, a melody made of mostly steps will often seem aimless and arbitrary, because nothing distinguishes it in our memory; the notes can seem to blur into one another inarticulately.
2. Suggest a clear overall tonal progression. Melodies should clearly inhabit a single key, or a pair of closely related keys; in J.S. Bach’s chorales, more keys may be implied, but normally only in the context of clear melodic departure. Although chromatic harmony is common in the 18th century (for example, a melodic arrival at a tonic could be harmonized with major or minor qualities of IV, VI or II7), the chromaticism usually does not disturb this principle of “clearly inhabiting a key” via melodic movement. One helpful way to think about this is to consider that even deceptive cadences and longer chromatic digressions in 18th century Western music will tend to occur in ways that would be undetectable if the melody were played without harmony.
3. The melody should occupy a singable pitch range, appropriate to its length of time.
a. Complete statements in 18th-century Western musics have a strong tendency to ranges around a 9th, 10th, or 11th.
b. A melody’s range should sound in good proportion to its length: a short phrase (2-3 mm) can seem well proportioned at about a 7th, a 16-bar melody can stretch as many as two octaves or more if the melody doesn’t seem to have left one range behind and forgotten it for another.
4. Reach, rhythmically, toward melodic goal notes, and strong beats. (Goal notes in this case are defined not only as the cadential endings of musical sentences, but a climax, an intermediary (pivotal subdominant) harmony before a cadence, the completion of a scalar ascent or descent, or the peak or trough of an arpeggio.)
Small note-values should be concentrated in weak beats of the measure, and reach toward strong beats.
Increase rhythmic activity leading up to goal notes.
Rhythmic activity should also be flowing easily on its way to a cadence.
Static, sparse rhythms have a place too: usually early in a melody, as the key is being established.
5. Distribute a melody’s points of motion and rest through the regions of the mode. Any two examples of similar motion, or any two examples of similar rest, will occupy different regions of its mode. If there is more than one “peak” in a melody, the peaks should be at different notes, so that one peak can have the feeling of leading to the other. The melodic goal notes of successive gestures should “progress” between one another, in ways that are sometimes similar to the note-to-note movement leading to each of those goals on a smaller time scale.