Second Species · Two notes against one
F Lydian
Two half notes per measure against each whole note of the cantus firmus. The final measure is a single whole note.
Cantus firmus: Fux, Gradus ad Parnassum (Figure 39) — 12 measures
Your line: written above the cantus firmus
To pass: complete every measure with no rule violations and score at least 80/100
How Second Species works
You now place half notes: two per measure. The downbeat (first half of each measure) is a strong beat, the second half is weak.
Strong beats must be consonant, exactly as in first species.
Weak beats may be dissonant — but only as a passing tone: approached by step and left by step in the same direction, filling the space between two consonances.
You may begin with a half rest: start your first note on the weak half of measure one if you like.
The rules
- Strong beats must be consonant. Every downbeat forms a consonance with the cantus firmus.
- Weak-beat dissonance must pass by step. A dissonant weak beat must be approached by step and left by step, continuing in the same direction.
- Two half notes per measure. Keep the species rhythm: half notes throughout, with a single whole note in the final measure.
- Begin and end on a perfect consonance. The first and last intervals must be a unison, perfect fifth, or octave against the cantus firmus (a fifth below the CF is not allowed when writing underneath it).
- No parallel or hidden fifths and octaves. Two voices may not move in the same direction into a perfect fifth or octave. Consecutive perfect intervals of the same size destroy voice independence.
- Singable melodic intervals only. No melodic tritones, sevenths, or leaps larger than an octave. Your line should be singable.
- Recover from leaps by stepping back. After a leap (especially a large one), change direction and move by step to fill in the gap.
- Aim for a single climax. Your line should have one highest note, ideally somewhere in the middle of the phrase.
- Keep the line varied. Avoid long chains of parallel thirds or sixths, and avoid mid-phrase unisons with the cantus firmus.
- Prefer contrary motion. Moving against the cantus firmus keeps the two voices independent. Aim for contrary motion at least ~40% of the time.
Tips
- • Think of each measure as one harmonic moment: the downbeat defines the interval, the weak half connects it to the next.
- • Passing tones make stepwise lines easy — leap on the strong beat, then fill in.
- • Watch fifths and octaves on successive downbeats: they still count as parallels even with a note in between.