1.3 Third Species — Four Notes per Chord-Zone
Definition. Third species places four notes per chord-zone in the added voice. This is florid melodic motion within a slow-moving harmonic frame. Passing tones, neighbor tones, anticipations, and arpeggiations are all available.
What this teaches. Third species teaches motivic shaping. With four notes per chord-zone, the student starts to develop melodic figures — the small-scale rhythmic and pitch shapes that will later become the motivic cells of the piece. Third species also tests the student’s ability to control voice independence at fast rhythmic rates.
Setup. A chord-graph path of 4-6 chords. The added voice plays four notes per chord (or, in 6/8 time, six eighth notes per measure if each chord is one measure long). Most of these notes should be chord tones; non-chord tones are limited to passing/neighbor/anticipation/escape tones with stepwise treatment.
Step-by-step procedure
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Begin with second-species line. Lay out a working second-species line. This becomes the structural skeleton.
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Identify the underlying motion at each beat. What are the chord tones the line passes through? At third-species rhythm, you’ll have time to traverse multiple chord tones within a single chord-zone.
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Develop motivic cells. Pick one or two short rhythmic figures and use them throughout. Two simple cells:
- Stepwise cell: four eighth notes ascending or descending stepwise, e.g., C5 D5 Eb5 D5.
- Turn cell: a melodic turn around a central pitch, e.g., D5 Eb5 D5 C5 (upper neighbor + lower neighbor).
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Place cells at structurally appropriate moments. Use ascending cells at moments of rising tension (before a Saddle); descending cells at moments of resolution (after a cadence); turn cells over stable chord-zones (Summits, Plateaus).
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Punctuate with rests where the line needs to breathe. A third-species line with continuous activity from start to finish lacks shape. Rest the line briefly between phrases.
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Ensure non-chord tones resolve. With four notes per chord-zone, the student has more freedom but more responsibility. Every non-chord tone should resolve by step to a chord tone — either of the current chord or the next.
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Approach the cadence with rhythmic acceleration. Speed up the surface rhythm as the cadence approaches. Hold the cadential note longer than the surrounding rhythm.
Worked example
Same cantus firmus. Develop a third-species added voice in 6/8 time with six eighth notes per measure.
| Measure | Chord | Voice line (six eighths) | Cell |
|---|---|---|---|
| 1 | Q777 | C5 D5 G5 D5 C5 D5 | turn cell + arpeggiation |
| 2 | Q877 | D5 C5 Bb4 C5 D5 Eb5 | descending stepwise cell, then ascent |
| 3 | Q787 | Eb5 D5 C5 D5 Eb5 G5 | turn + ascent |
| 4 | Q877 | G5 F5 Eb5 D5 C5 Bb4 | descending cascade — resolution figure |
| 5 | Q777 | A4 — — — — — | cadence: held A4, stable |
The cadence held note A4 at chord 5 is approached by Bb4 → A4 (the leading-interval pair). Voice 4 of the cantus firmus does the same Bb→A; the added voice mirrors it at the appropriate octave. This is parallel motion at the cadence — but the parallelism is intentional: both voices descending by single semitone is the OTH cadential gesture, which is what we want.
Common errors in third species
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Continuous activity without shape. Six eighths per measure for five measures = 30 notes. If they’re all the same rhythmic value, the line sounds metronomic. Vary by introducing held notes, rests, or larger rhythmic values.
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Cell repetition without variation. Using the same rhythmic cell six times without modification creates monotony. Vary at least one element per recurrence: pitch, direction, or rhythm.
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Unresolved non-chord tones. With four notes per chord-zone, it’s easy to slip in a non-chord tone and forget to resolve it. Check every beat.
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Voice-crossing under high rhythmic activity. When the line is moving fast, it’s easier to cross under (or over) another voice. Watch the register carefully.