Counterpoint is the art of combining independent melodic lines so they sound clear, balanced, and expressive together. This cheat sheet helps Grade 11-12 music theory students review the basic rules used in species counterpoint, invertible counterpoint, and fugue writing. These ideas are important for analyzing Baroque music, composing short studies, and understanding how composers create complex textures from simple motives.
The core concepts include consonance and dissonance, melodic independence, voice-leading rules, and imitation. Species counterpoint builds control one rhythm layer at a time, while invertible counterpoint tests whether two voices still work after switching positions. Fugue basics focus on how a subject is introduced, answered, developed through episodes, and combined in entries such as stretto.
Key Facts
- In first species counterpoint, each note in the counterpoint sounds against one cantus firmus note, and vertical intervals should be consonant.
- Perfect consonances are unison, octave, fifth, and sometimes fourth depending on context, while imperfect consonances are third and sixth.
- Avoid parallel perfect fifths and parallel octaves because they weaken the independence of the voices.
- In second species counterpoint, two notes sound against each cantus firmus note, and the strong beat should normally be consonant.
- A passing tone is a stepwise dissonance that moves between two consonant tones in the same direction.
- In invertible counterpoint at the octave, an interval number changes by the rule original interval + inverted interval = 9, such as 3 becoming 6.
- A fugue subject is the main melodic idea, and the answer is the subject restated in another voice, usually at the dominant or tonic level.
- A stretto occurs when a new subject entry begins before the previous subject entry has finished.
Vocabulary
- Counterpoint
- Counterpoint is the combination of two or more independent melodic lines that fit together harmonically.
- Cantus Firmus
- A cantus firmus is a fixed melody used as the foundation for writing counterpoint.
- Species Counterpoint
- Species counterpoint is a step-by-step method for learning counterpoint through controlled rhythmic patterns.
- Invertible Counterpoint
- Invertible counterpoint is counterpoint designed so the voices can switch positions and still sound correct.
- Fugue Subject
- A fugue subject is the main theme that is introduced and imitated throughout a fugue.
- Episode
- An episode is a passage in a fugue that develops motives from the subject or countersubject between full subject entries.
Common Mistakes to Avoid
- Using parallel fifths or octaves, which is wrong because both voices move together in a way that destroys their independence.
- Treating every fourth as automatically consonant, which is wrong because a fourth above the bass is often considered dissonant in strict counterpoint.
- Placing a dissonance on a strong beat without preparation or resolution, which is wrong because dissonance usually needs controlled voice leading.
- Writing an invertible counterpoint line without testing the inversion, which is wrong because some intervals that work in one position may become problematic after inversion.
- Calling any repeated imitation a fugue, which is wrong because a fugue has organized subject entries, answers, episodes, and developmental procedures.
Practice Questions
- 1 In invertible counterpoint at the octave, what interval does a 3rd become after inversion?
- 2 A counterpoint line moves from C to D to E while the cantus firmus holds C, with D as a passing tone. Is D consonant or dissonant against C?
- 3 Identify the problem if two voices move from C-G to D-A in the same direction and keep the interval of a perfect fifth.
- 4 Explain why a fugue needs both melodic independence and recognizable repetition of the subject.