Three-voice counterpoint introduces texture — the sense of space and weight that comes from adding a third melodic voice. New freedoms (chord tones can be more freely chosen) come with new challenges (maintaining independence of three voices is harder).
Moving to Three Voices
Three-voice counterpoint introduces the full vertical dimension of tonal music: with three voices, every note can belong to a complete triad. The additional voice adds weight, colour, and harmonic clarity — but it also introduces new voice-leading challenges. With three independent voices moving simultaneously, the probability of parallel perfect consonances, voice crossing, and tonal confusion increases. Maintaining the independence of all three voices — ensuring that each has its own distinct melodic identity — requires more skill than two-voice writing.
In three-voice counterpoint, the voices are labelled by register: soprano (top), alto or tenor (middle), bass (bottom) — though the precise register depends on the specific exercise. The cantus firmus may appear in any voice. When it is in the bass, the upper two voices must be composed; when it is in the tenor (middle), both the soprano and bass must be written; when it is in the soprano (top), the two lower voices must provide support. Each arrangement creates different compositional challenges and reveals different aspects of contrapuntal technique.
Triadic Completeness
With three voices, every sonority can be a complete triad. This is a fundamental change from two-voice writing, where every interval was either a third, fifth, sixth, or octave but no complete triadic sonority was possible. In three voices, the student must decide for each beat: which root, third, and fifth combination is needed? Should the chord be in root position (root in bass), first inversion (third in bass), or second inversion (fifth in bass)? Second inversions are treated with great caution in species counterpoint because the fourth above the bass is dissonant — the second-inversion triad is functionally unstable.
The choice of which note to double when only three voices are available is governed by specific principles. In root-position triads, double the root. In first-inversion triads, double the root or the fifth (not the third, which is the chord member already in the bass). In second-inversion triads (used cautiously), double the bass note (the fifth of the chord). Never double the leading tone of the key — when it resolves up to the tonic, two voices on the leading tone will produce parallel octaves on the tonic.
New Rules and Exceptions
Several rules of two-voice counterpoint are relaxed or modified in three voices:
- The fourth between upper voices is consonant. The fourth (which is dissonant in two voices between bass and soprano) is now permissible between soprano and alto, or between alto and tenor. A fourth between upper voices does not create the unstable bass relationship that makes the fourth dissonant.
- Consecutive perfect consonances are still prohibited between any two voices. Parallel fifths between soprano and tenor are just as forbidden as parallel fifths between bass and soprano. The student must check every pair of voices for parallel perfect consonances at every beat.
- Complete triads are now expected. The harmonic goal of each measure should be a recognisable triad (major, minor, or occasionally diminished in a limited context). An incomplete triad (one with a missing third or fifth) is acceptable only in specific circumstances — typically at strong cadences where the missing chord tone is implied.
- Voice crossing is to be avoided. The soprano dropping below the alto, or the alto dropping below the bass, creates momentary confusion about the harmonic identity of each voice. Brief voice crossings are acceptable in specific contrapuntal contexts but should be exceptional.
- Voice overlapping is also to be avoided. The soprano moving below where the alto was on the previous beat, or the alto moving above where the soprano will be on the next beat, creates similar confusion.
Spacing and Doubling
Three-voice spacing — the vertical distance between adjacent voices — is critical to the sound. Standard practice keeps the upper two voices within an octave of each other and allows the bass to be more widely separated. A common spacing for a triad: bass on C, tenor on G (a fifth above), soprano on E (an additional third above) — total range an octave plus a third. This spacing produces a balanced, resonant sonority.
Avoid wide spacing between the upper two voices (more than an octave between soprano and tenor), which produces a "thin" sound with a gap in the texture. Avoid cramped spacing in any pair of voices (two voices within a third of each other can sound muddy, especially in low registers). The bass and tenor may be widely separated (often by an octave or more) without producing a problem, because the bass register naturally accepts wider spacing.
Three-Voice Texture and Resonance
Three voices produce a richer acoustic resonance than two. The relationship between the three voices creates an implied harmonic rhythm — a sense of chord-to-chord motion even in species exercises. The best three-voice counterpoint has the quality of organ registration: each voice occupies its own register, each moves independently, and the combined sound is full without being muddy.
Bach's three-part sinfonias (BWV 787-801) are the textbook examples of three-voice counterpoint at its highest level. Each sinfonia maintains three genuinely independent voices throughout, each with its own thematic material and rhythmic profile. The Sinfonia in F minor (BWV 795) is often cited as the most contrapuntally dense — three voices in chromatic counterpoint with multiple suspensions and a constantly shifting harmonic centre, yet each voice remains audibly distinct.
Practical Approach
When writing three-voice exercises, plan the harmonic skeleton first: what triad will appear on each beat? Then place the bass, choosing inversions and root motion to produce a flowing bass line. Then add the two upper voices, ensuring that each has its own melodic shape and that no parallel perfect consonances arise between any pair of voices. Check each voice individually as a melody, and check each pair of voices as a two-voice counterpoint.
Students should sing or play all three voices, either on piano (two hands plus voice) or using notation software playback. The three-voice sonority should sound clear and balanced — no single voice dominating, no register too crowded. If the texture sounds thick or unclear, the spacing is probably wrong; if it sounds thin, the doublings are probably wrong; if a voice is inaudible, that voice probably lacks melodic profile.
Sources and Further Reading
- Fux/Mann. The Study of Counterpoint. Norton. Part III.
- Jeppesen. Counterpoint. Prentice-Hall. Chapters on Three-Voice Counterpoint.
- Open Music Theory — Three-Voice Counterpoint (openmusictheory.net, CC BY-SA 4.0).
- Gauldin. A Practical Approach to 18th-Century Counterpoint. Waveland Press. Chapter 7.
- Aldwell and Schachter. Harmony and Voice Leading. Schirmer/Cengage.