SATB · voice leading · on a staff
Four-part harmony generator
Type the chords, and get four parts a choir can sing: a smooth soprano line, and alto, tenor and bass voiced the way a choral arranger would, with no parallel fifths or octaves and every chord with its third. See them on a staff, hear them together, or hear one part alone to learn it. Free, with no account.
How to use it
- Type your chords in the box, like C Am F G7 C. Bar lines, commas and slash chords like G/B are fine.
- Press Play to hear the four parts, and tap a part's name to leave it out: hear the others and sing that part yourself.
The four parts and their ranges
Each part's comfortable range, as most choir music keeps it. The generator keeps every part inside these, around the middle.
| Part | Range | Written on |
|---|---|---|
| Soprano | C4 to A5 | The treble staff, stems up |
| Alto | F3 to D5 | The treble staff, stems down |
| Tenor | C3 to A4 | The bass staff, stems up |
| Bass | E2 to E4 | The bass staff, stems down |
How a chord is voiced for four
A triad has three notes, so with four voices one is doubled: usually the root, which sounds most stable. The third is never left out, because it says whether the chord is major or minor; the fifth can be, when the lines need it.
In a seventh chord all four notes are sung, and the seventh is never doubled. It falls by step into the next chord, as G7's F falls to E in C.
Learning a part by ear
Leave your own part out and play the other three: you hear where your note sits in each chord, and singing it into the gap is the best practice for holding a part in a choir.
To learn parts of real songs this way, with a guide voice and each note you sing shown in pitch and time, try the app.
Free tools by Stackapella
You've voiced the chord. Now sing all four parts yourself.
Stackapella teaches you to sing harmony one part at a time, right in your browser.
- A guide sings your partHear your line over the others, slow it down, then take your turn.
- Your notes light upEach note shows where you landed, and a hint when to go up or down.
- Record every part yourselfStack your takes in time until you're the whole choir.
- Every course free
- Open source
- No ads, no tracking
Questions
What is SATB?
Soprano, alto, tenor and bass: the four parts of a mixed choir, from highest to lowest. Sopranos and altos are usually women's and children's voices, tenors and basses men's. Four-part harmony gives each part one note of every chord.
What are the voice-leading rules?
The ones taught in every harmony class: each part moves as little as it can, by step where possible; no two parts move in parallel fifths or octaves; parts don't cross; the upper three stay within an octave of each other; every chord has its third; and the leading tone rises to the tonic, while a seventh falls by step. The generator follows all of them.
Why avoid parallel fifths and octaves?
Two parts moving together a fifth or an octave apart blend so well that they sound like one part, and the harmony thins from four voices to three. Keeping them apart keeps each line its own.
What range does each part sing?
Roughly: soprano from middle C to A5, alto from F3 to D5, tenor from C3 to A4, and bass from E2 to E4. The generator keeps each part in an easy middle range, so most choirs can sing it as written.
What does a slash chord like G/B mean?
Play or sing G, with B in the bass. The generator keeps that bass note, so a line like C, G/B, Am walks down step by step, as written.
Can I hear one part alone?
Yes. Tap a part's name under the staff to leave it out, then play: you hear the other three and sing the missing one, or leave three out to hear the one you're learning.
Which chords can it voice?
Major, minor, diminished and augmented chords, sus2 and sus4, sixths, added ninths, and sevenths of every kind. Richer chords, like 9 or 13, are sung as the seventh chord under them, so four voices can sing them.
Is it free?
Yes: no account and no ads. Your chords and settings stay on this device.
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