30.4: Third Species Counterpoint
30.4 Third Species Counterpoint
In third species, one writes four quarter notes to each whole note in the cantus firmus. Use the following rules.
- Begin on an octave or unison. Write four quarter notes to each whole note in the cantus firmus except for the final measure.
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End on a whole note on an octave or unison with the penultimate measure using one of the following formulas:
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If the cantus firmus is in the lower voice, the penultimate measure of the upper voice can be:
- 4^ –5^ –6^ –7^ , or
- 2^ –1^ –6^ –7^ (the cambiata —see 5.b. below)
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If the
cantus firmus
is in the upper part, the penultimate measure of the lower voice is 7^ –5^ –6^ –7^ .
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If the cantus firmus is in the lower voice, the penultimate measure of the upper voice can be:
- Each downbeat should be a consonance.
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When crossing barlines, apply the following:
- “Imperfect” consonances (3rds and 6ths) can be approached in any manner.
- “Perfect” consonances (unisons, 5ths, 8ves, 12ths) may only be approached in contrary motion in order to avoid direct 5ths and direct 8ves.
- Do not repeat notes across barlines
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Allowable dissonances:
- Passing tones are allowable dissonances (but never on the first beat of the measure).
- The cambiata (see the melodic contour in third measure of the example below) is allowed but only with the second note of the measure as the only dissonant interval.
- Direct 5ths and direct 8ves are not allowed and occur when an 8ve or 5th on a downbeat is approached through similar motion.
Go to Third Species Practice Exercises .