Species Counterpoint |
First species in three partsIn counterpoint in more than two parts, greater attention must be paid to consonance and dissonance. There will be more pairs of notes to check to ensure that consonances occur where they are required, and that dissonances are properly prepared and resolved. Also in three or more parts it is possible to present a full harmonic triad. In order to be consonant, the triad must or course be in root position or first inversion; the 6-4 chord is a dissonance in strict counterpoint one of the upper notes makes a fourth with the bass. As a general principle, try to achieve a balance between the integrity of the individual parts and the beauty of full three-part harmony; that is, you should aim for full triads whenever possible, but not at the expense of good part-writing or an elegant line.
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| Ex 4.1 |
Fux goes to great length to explain this by comparing the four parts of this example (the bass is always the same and may be thought of as a cantus firmus). (a) is Fux's preferred realisation in three parts, because the middle voice seems to him the most "natural": the tenor is led "gracefully" from e1 to c1 as the bass moves from C to E. (b) is "not to be considered wrong," but there is less variety in the tenor part: there is a leap to a, followed by a return to the same note two bars later. (c) and (d) are "not...altogether bad," but he does not like all three parts moving in the same direction. In (c), moreover, the upper parts in bar 2 form a diminished fifth - an interval which would be wrong in two parts and is somewhat awkward in three. (d) begins as an inversion of (c): the similar motions in all parts results in consecutive sixth chords in bars 2-3, which Fux does not like because they occur on successive strong beats. |
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| Ex 4.2 |
Consecutive fifths and octaves should always be avoided; so should approaching a unison by similar motion. With similar motion to the fifth or octave, the rules are more complicated. As a general rule, you should avoid similar motion to the fifth or octave between the outer parts, but they are permitted elswhere (i.e. between the lower two or the upper two parts). You may also approach the octave of a final cadence by similar motion (see the last two bars of this example). And fifths may be approached by similar motion in the outer parts so long as the treble moves by step (bars 7-8). But in all these "exceptional" cases, the third part does not move in the same direction; in fact the movement of all parts in the same direction is generally to be avoided in three-part counterpoint. |
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| Ex 4.3 |
As before, all chords must be consonant. The first chord must begin with the "key note" in the bass, regardless of the position of the cantus firmus; each of the notes in the first chord must belong to the "tonic triad," but it is not necessary to begin with the full harmonic triad. The final cadence must include linear contrary motion to the octave or unison. If this occurs in the upper parts, the bass will leap down a fifth (or up a fourth) and so convey a harmonic progression of V-I. Here are some cadences in three parts - the cantus firmus voice always falls to the tonic. |
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