Definition
Musica ficta indicates the accidentals (sharps and flats) that the performer or composer adds to the notes of the diatonic system for two purposes: to make the cadence stronger and to avoid harsh intervals, above all the tritone. In Fux's counterpoint the accidentals are few and predictable: you learn to use them as rules of writing.
The leading tone at the cadence
In the modal cadence the voice that rises to the finalis must do so by semitone. If the mode has a whole tone below the finalis, the penultimate note is raised:
| Mode | Natural penultimate | Altered | Cadence |
|---|---|---|---|
| Dorian (D) | C | C# | C#–D |
| Mixolydian (G) | F | F# | F#–G |
| Aeolian (A) | G | G# | G#–A |
| Lydian (F) | E | E (already a semitone) | E–F |
| Ionian (C) | B | B (already a semitone) | B–C |
| Phrygian (E) | D | D stays natural | D–E against F–E |
In Phrygian nothing is raised: the semitone is already in the descending voice (F–E) and the upper voice rises by a whole tone (D–E). This is the Phrygian cadence, the only one in which the penultimate sixth is minor if the melody is below (D above F).
B-flat
- In Lydian the fourth F–B is augmented: for this reason in practice Bb is often used, and Lydian with Bb coincides with the modern Ionian on F.
- In Dorian Bb is used when the line touches B near F (to avoid F–B) or when it rises to B and falls back to A: the formula A–Bb–A is typical.
- Old mnemonic rule: a note above A that immediately returns down is sung fa (that is, Bb).
The tritone to avoid
- Melodically: no leap F–B or B–F; and beware also of the outlined tritone, that is, a line that goes from F to B by step or with few notes and stops there.
- Harmonically: in two voices the augmented fourth and the diminished fifth are dissonances. In florid species they may appear only as passing notes.
- Cross-relation (mi contra fa): avoid one voice singing B and the other, immediately afterward, Bb, or C and C#, in different voices. The accidental must stay in the same voice.
Example in D Dorian
Cantus firmus D F E D G F A G F E D. Counterpoint above in first species: A D C D B A C E D C# D. The C# of the penultimate bar forms a major sixth with E and rises to D forming the octave. Without C# the sixth would be minor and the cadence would sound weak, almost Phrygian.
Counterpoint below: D A G B E A F G D C# D, with C#–E a minor third that opens out onto the unison D.
Typical mistakes
- Raising the penultimate note in Phrygian (D#): it destroys the character of the mode.
- Raising the leading tone and then not resolving it by rising to the finalis.
- Doubling the altered note in three or four voices: the leading tone is never doubled.
- Using Bb and B natural very close together in different voices, creating a cross-relation.
Modern application
- Modal pop: in a song in D Dorian (vamp Dm–G) the use of A or A7 with C# before the return to Dm is exactly the musica ficta leading tone; leaving it natural (Am) preserves the modal color.
- Film scores: alternating cadences with a leading tone and Phrygian cadences (Bb–A in D minor, or F–E in A) is a simple way to change emotional weight from one scene to another.
- Choirs: in amateur choirs the altered leading tone is the point where intonation sags; write it by step and give it to the most secure voice.
Related topics
Church modes, modal clausulae and cadences, Andalusian and Phrygian cadence, consonances in strict counterpoint.