The four voices and their ranges
- Soprano: C4–G5 (up to A5)
- Alto: G3–D5 (comfortable up to C5)
- Tenor: C3–G4 (up to A4), written in treble clef an octave higher
- Bass: E2–C4 (up to D4)
Doublings
A triad has three notes, there are four voices: one note is doubled.
- Root position: double the root.
- First inversion: usually double the soprano or a stable note, never the leading tone.
- 6/4: double the bass (the fifth).
- Diminished triad (vii° in first inversion): double the third (the bass).
- Never double the leading tone or the seventh of the chord.
- In the V7 – I cadence it is normal to have one of the two chords incomplete (without the fifth, with the root tripled).
Procedure
- Write the bass first, then the soprano (the outer voices must form good two-part counterpoint).
- Fill in alto and tenor looking for common tones and stepwise motion.
- Check for parallel fifths and octaves between all six pairs of voices.
Example: I – IV – V7 – I in C (from bottom to top)
- I: B C3, T G3, A E4, S C5
- IV: B F2, T A3, A F4, S C5
- V7: B G2, T D4, A F4, S B4
- I: B C3, T C4, A E4, S C5
The soprano C–C–B–C and the alto E–F–F–E barely move; the seventh F (alto) falls to E, the leading tone B (soprano) rises to C.
Close and open position
Close: the three upper voices within an octave (compact sound, piano-like). Open: more space between tenor and alto (wide choral sound).
Real example
The chorale “O Haupt voll Blut und Wunden,” which Bach harmonizes several times in the St. Matthew Passion (1727), is the classic text for studying doublings and four-part voice leading; the same principles govern gospel vocal arrangements and multitrack pop choirs.