Imitation, Canon and Fugue
Imitation begins when one voice presents an idea and another repeats it later. A round keeps repeating the full melody, a canon follows a strict rule and a fugue alternates imitative entries with freer development.
- one idea, several entries
- delay creates overlap
- strictness differs by form
What is imitation?
A voice states a recognizable motive or phrase. A second voice enters later with the same contour, either at the same pitch or transposed.
The delay matters because the first voice continues while the second begins. The composer must make the idea work as melody and as accompaniment to itself.
How do round, canon and fugue differ?
- Round
Every voice performs the same complete melody from the same pitch after a fixed delay. The cycle can repeat continuously.
- Canon
One voice follows another according to a rule. The follower may enter at another interval, in inversion, backward or at another speed.
- Fugue
Voices enter successively with a subject and answer, then continue through freer contrapuntal episodes and later subject returns.
- Free imitation
A motive returns recognizably without governing an entire strict form.
What happens in a fugue exposition?
The first voice states the subject alone. A second voice presents the answer, usually around the dominant level, while the first continues.
That continuing line may become a recurring countersubject. Further voices enter with subject or answer until every voice has joined.
A real answer transposes the subject exactly. A tonal answer adjusts one or more intervals to prevent the music from leaving the tonic too soon.
What is an episode?
An episode is a passage between full subject entries. It often develops a fragment through sequence, inversion or exchange between voices.
Episodes move the harmony, vary the texture and prepare a later return. The subject remains the identity of the fugue even when it is temporarily absent.
Which transformations can the idea undergo?
| Technique | What changes |
|---|---|
| Transposition | every pitch moves by an interval |
| Inversion | rising intervals become falling intervals |
| Augmentation | note values become longer |
| Diminution | note values become shorter |
| Stretto | a new entry begins before the previous one finishes |
A transformation must preserve enough rhythm and contour for the source to remain recognizable.
How do you follow several voices?
- Memorize the opening subjectsing its rhythm and first intervals.
- Mark every clear entrynote voice, pitch level and time.
- Follow one voice through the overlapresist jumping immediately to the newest entry.
- Separate entries from episodeslisten for the full subject versus fragments.
How can you write a simple imitation?
Create a two-bar melody with a clear rhythm and mostly stepwise motion. Start the second voice one bar later. Rewrite the continuation of the first voice until both lines remain singable and the strong beats are controlled.
Test several delays and entry pitches. A good subject is not automatically a good canon; the overlap determines which version works.
Keep going
Everything in harmony
- Four-Part Chorale Style
- Species Counterpoint
- Imitation, Canon and Fugue
- Counterpoint in Pop
- Jazz Harmony
- Twentieth-Century Techniques