# Music Theory for the 21st-Century Classroom

## Section30.3Second Species Counterpoint

In second species, one writes two half notes against a cantus firmus in whole notes. (Second species can also include writing three half notes against a cantus firmus of dotted whole notes in $$\begin{smallmatrix}3\\2\end{smallmatrix}$$.) The rules are generally the same as first species except that one simple dissonance is allowed in second species: the passing tone. Please see the details below.
1. Begin your counterpoint with a half note at the octave or unison on either the first or third beat of the measure; if starting on the third beat, put a half rest at the beginning of the measure.
2. End with a whole note on an octave or unison, using one of these concluding formulas:
1. If the cantus firmus is in the lower part, approach the final octave with intervals of a fifth and sixth ($$\hat{6}$$$$\hat{7}$$ against $$\hat{2}$$ in the cantus firmus).
2. If the cantus firmus is in the upper part, approach the final octave or unison with the intervals of a fifth and third ($$\hat{5}$$$$\hat{7}$$ against $$\hat{2}$$ in the cantus firmus).
3. Phrygian mode has an exception: if the cantus firmus is in the upper part, approach the final octave or unison with the intervals of a sixth to a third ($$\hat{4}$$–♭$$\hat{7}$$ against ♭$$\hat{2}$$ in the cantus firmus).
3. Of the two half notes you write in each measure, the first must always be a consonance (unison, 3rd, 5th, 6th, 8ve, or compound interval equivalent). If the second is a dissonance, it can only be a passing tone (approached and left by step). Otherwise, the second note must be a consonance. The only allowable leaps are the same as in first species.
4. When crossing barlines, apply the following:
1. “Imperfect” consonances (3rds and 6ths) can be approached in any manner.
2. “Perfect” consonances (unisons, 5ths, 8ves, 12ths) may only be approached in contrary motion in order to avoid direct 5ths and direct 8ves.
3. Do not repeat notes across barlines
5. Avoid 8ves on consecutive downbeats and avoid 5ths on consecutive downbeats unless there is the leap of 4th occurring after the 8ve or 5th on the downbeat
Notice that dissonant interval numbers (2, 4, tt, 7) are circled to highlight that they must be handled in a special manner.