How to write a cantus firmus

How to write a cantus firmus in the style of Fux: begin and end on the final, approach it by step, mostly stepwise motion, one climax. With an example you can hear.

One line

Writing a cantus firmus

Before writing against a cantus, write one. A cantus firmus is a short, plain melody in whole notes: it sets out the mode, moves mostly by step and has a clear arc. Every species exercise starts from one.

Write a cantus

Fux's Dorian cantus: D to D, one climax on A, and three small leaps, each answered by a step back.

Begin and end on the final

The first and last notes are the final of the mode, in the same octave. That is what makes the mode clear.

D at both ends: the mode is clear from the first note and the last.

Approach the final by step

Usually from the note above. A step up from the leading tone below also works, but the cantus itself stays in the mode.

Left: E steps down to the final. Right: the leap from A into D sounds unfinished.

Mostly steps, a few leaps

One to three leaps give the line character. After a leap, step back the other way; never two leaps in a row.

Two leaps up, F and G, each answered by a step back down.

One climax, a singable range

The highest note comes once, somewhere in the middle. Keep the whole line within about a 10th, with no repeated notes and nothing outside the mode.

The climax, A, comes once, in the middle. The whole line spans a 5th.

Practise it now

Write how to write a cantus firmus exercises in your browser. Every rule is checked as you write, and you can hear your lines.

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