Audio: second species counterpoint (0:09)
second species counterpoint sings second species counterpoint in the key of C. The second species counterpoint figure shows the counterpoint melody in the top part of the score and the fixed melody in the bottom part.
Second species counterpoint introduces rhythm and dissonance.
The meter in second species is duple meter. There are two half notes in the counterpoint melody to every one whole note in the fixed melody. All the music contains whole notes and half notes except that the first note of the counterpoint melody can be a rest.
Resolution is the movement from dissonance to consonance. Second species counterpoint has rules for resolving dissonance.
The first note in each bar of the counterpoint melody must be consonant with the fixed melody. The second note in each bar of the counterpoint melody can be consonant or dissonant.
A consonant second note can move by step or leap. The second note can leap by an interval greater than a third. This is a new rule that helps to avoid direct motion to a perfect consonance. The thinking behind the rule is that a leap of more than a third masks the effect of direct motion to a perfect consonance, whereas a leap of a third does not. In second species counterpoint the counterpoint melody moves from a sixth in bar 7 to a fifth in bar 8, which is direct motion to a perfect consonance. The motion is acceptable because the intervening second note in bar 7 leaps down a fourth from C to G.
A dissonant second note can only move by step, not by leap.
The dissonance can be an interval of a second, fourth or seventh, but not a tritone, which is still forbidden. There are two dissonances in second species counterpoint: a seventh in the first bar and a fourth in the fifth bar.
The writer of counterpoint invariably gets tangled up, usually sooner rather than later. One solution, introduced in second species counterpoint, is eminently sensible: a large leap is allowed in the counterpoint melody. The solution is constrained as usual: the leap must be up not down and must be either a minor sixth or an octave.