hmmonySee the parallel fifths before you hand the exercise in.
hmmony checks four-part harmony exercises as you write them. Enter the soprano, alto, tenor and bass, and it marks parallel fifths and octaves, notes outside a voice's range, wide spacing and other voice-leading errors — and explains each one.
Thank you — we'll email you when there is a place. Nothing else.
Or try the checker now — it works without an account.
What a check looks like
A V–vi progression in C major, with every voice moving up. The checker marks the notes involved and says what is wrong.
What it checks
- Parallel fifthsTwo voices a perfect fifth apart move to another perfect fifth.
- Parallel octaves and unisonsTwo voices an octave (or unison) apart move to another octave or unison.
- Diminished fifth to perfect fifthA diminished fifth moves to a perfect fifth, with the bass involved.
- Hidden (direct) fifths and octavesSoprano and bass move in the same direction into a perfect fifth or octave, with the soprano leaping.
- Voice rangeA note is outside the usual range of its voice.
- SpacingMore than an octave between soprano and alto, or between alto and tenor.
- Voice crossingA lower voice is above a higher voice in the same chord.
- Voice overlapA voice moves past where the neighbouring voice just was.
- Leap larger than an octaveA voice leaps more than an octave.
- Augmented melodic intervalA voice moves by an augmented interval, such as an augmented second or fourth.
- Leap of a seventhA voice leaps a seventh.
- Doubled leading toneTwo voices sing the leading tone in the same chord.
- Leading tone in the soprano does not resolveThe leading tone in the soprano does not move up a step to the tonic.
Every finding comes with a written explanation of the rule and the usual way to fix it. Read them all.
For students
The feedback arrives while you are still writing the exercise, not a week later when it comes back marked.
- A grid for the four voices, with the notes drawn on a grand staff as you type.
- Checks rerun on every note you change.
- An explanation under each finding: what the rule is and why it exists.
- With an account: save exercises, and ask for an AI explanation of a specific passage.
For teachers
- Create an assignment set and add exercises: a given bass or melody to harmonise, or a free progression.
- Give your students the six-character code.
- See who has handed in what, with the checker's findings for each exercise, as the work arrives.
What it does not do
hmmony checks voice leading. It does not name chords, realise figured bass or judge whether a progression is a good choice, so an exercise with no findings is not necessarily a correct answer. It is a way to catch the mechanical errors early, so lesson time can go on the music.
Get early access
hmmony is new. Leave your email and we'll write when there is a place for you or your class.
Thank you — we'll email you when there is a place. Nothing else.