Third species introduces four quarter-note counterpoint notes against each whole-note cantus firmus. The faster motion allows neighbour tones, passing tones on multiple beats, and more elaborate melodic lines.
The 4:1 Ratio and Its Implications
Third species counterpoint places four quarter notes in the counterpoint voice against every whole note of the cantus firmus. This 4:1 ratio creates three interior beats between each cantus firmus note: only the first beat (coinciding with the cantus firmus note) requires a consonance; beats 2, 3, and 4 permit passing tones and neighbour tones under specific conditions. Compared to second species, the writing now feels genuinely melodic — a flowing line in continuous motion against the slow cantus firmus.
The increased melodic freedom of third species allows for genuinely flowing melodic lines — lines that can ascend or descend stepwise for several beats, introducing multiple dissonances in succession as long as each is a passing or neighbour tone. A line moving C-D-E-F (with D and E as passing tones between the consonant C and F) is entirely acceptable. A line moving E-F-G-A works if E and A fall on consonances and F and G are passing tones approached and left by step. The result begins to sound like real music — like the running quarter-note voices in Palestrina's polyphony or in Bach's chorale preludes.
New Dissonances: Neighbour Tones and the Cambiata
Third species introduces the neighbour tone (also called an auxiliary note): a note that steps away from a consonant tone and immediately returns (C-D-C, where D is the upper neighbour, or C-B-C, where B is the lower neighbour). The neighbour tone is dissonant (if D is a second above the cantus firmus note) but harmless — its immediate return to the consonant origin note clarifies its function.
The double neighbour figure (C-D-B-C or C-B-D-C) is also permitted: two adjacent neighbours of the same note appearing in sequence before returning. This creates characteristic angular melodic contours that are beautiful in third species. The figure occupies all four beats of a measure and produces a distinctive arching shape against the cantus firmus.
The cambiata figure (changing note) from second species also appears in third species. The pattern down-by-step, down-by-third, up-by-step (C-B-G-A) is permitted even when the B is dissonant (only the second note of the figure may be dissonant), because the specific voice-leading pattern is grammatically established by tradition. Jeppesen identifies this figure in dozens of passages from Palestrina, where it functions almost like a melodic idiom — a recognised gesture that listeners parse as a single unit rather than as four separate notes.
The Échappée and Other Specialised Figures
Third species also makes possible the échappée (escape tone): a non-chord tone approached by step in one direction and left by leap in the opposite direction. The échappée is the inverse of the appoggiatura (approached by leap, left by step). It is rarely permitted in strict species counterpoint — Fux discourages it and Jeppesen finds it only in specific cadential contexts — but it appears in tonal music as a standard ornamental tone and should be recognised when it occurs.
The anticipation, in which a chord tone arrives on a weak beat slightly before the harmony shifts to make it consonant, is generally avoided in third species exercises but is common in later tonal music. The consonant skip — a leap from one chord tone to another while the harmony is unchanged — is permitted within a single measure and is one of the main ways to introduce angular shapes against a single cantus firmus note.
Melodic Guidelines for Third Species
With four notes per beat, melodic shape becomes more important. The basic guidelines:
- The line should have clear direction — generally arch-shaped, with a single high climax note that occurs roughly two-thirds of the way through the exercise.
- Avoid repeated notes, which sound monotonous in this species. The same pitch should rarely sound on two consecutive beats.
- Leaps should still be followed by stepwise contrary motion when possible. After a leap of a fourth or larger, the next note should usually step back in the opposite direction.
- The species should produce a genuinely singable line. If you cannot sing it comfortably at moderate tempo, it probably has a voice-leading problem.
- Avoid having the climax note appear more than once. The high point should be unique to give the line its overall shape.
- Manage your dissonances proportionally: a measure with three passing tones followed by another measure with three passing tones can become exhausting. Alternate between active measures and more consonant measures (those with consonant skips and few passing tones).
The Next-Note Test
There is a classic test for third species quality: the "next-note test." At any point in the line, ask: is the next note predicted by the current motion? If you are stepping upward, does the next note continue the step or begin a new gesture? Unpredictable motion — motion that seems to arrive from nowhere — indicates either an error or a poor compositional choice. The student should be able to justify every note: this is the passing tone between X and Y; this is the upper neighbour of Z; this is a consonant skip approaching the climax; this is the resolution of the prior leap.
Beat-by-Beat Interval Analysis
A useful exercise is to label every interval against the cantus firmus on every beat. On beat one of each measure, every interval must be consonant (third, fifth, sixth, octave — but not fourth). On beats two, three, and four, dissonances are permitted only as passing or neighbour tones. Consonant intervals on weak beats are permitted but should not be perfect consonances if reached by leap, since a leap to a perfect fifth or octave on a weak beat may create the illusion of a structural perfect interval.
Practical Exercise
Using the cantus firmus C-D-F-E-G-F-D-C, write a third species counterpoint above it. The opening should begin with a quarter rest followed by three quarter notes, with the first sounding note a perfect consonance. Plan your climax note — the highest pitch in the line — to fall somewhere in the middle measures. Build toward it gradually and descend from it toward the cadence. Verify each dissonance individually: is it approached by step? Is it left by step in the same direction (passing tone) or returned to (neighbour tone)? If not, revise.
Sources and Further Reading
- Fux/Mann. The Study of Counterpoint. Norton. Part II, Chapter 4.
- Jeppesen. Counterpoint. Prentice-Hall. Chapter 6.
- Open Music Theory — Species Counterpoint (openmusictheory.net, CC BY-SA 4.0).
- Gauldin. A Practical Approach to 18th-Century Counterpoint. Waveland Press.
- Kennan. Counterpoint. Prentice-Hall.