Major · minor · barbershop 7th
Just intonation tuner
Tune your note to the chord, not the piano: sing over a drone and see how close you are to pure. Free, with no account.
How to use it
- Pick the root at the top and the chord: Major, Minor or Barbershop. Tap Start the drone and allow the microphone: the drone holds the root and its pure fifth.
- Sing a note of the chord, in any octave. It names the chord tone you're on and how many cents you are from pure; the meter has pure in the middle and the piano's pitch marked beside it. Within 6 cents of pure, it says Ringing.
- Tap a tone's tile to hear it pure over the drone. More has the drone's level, its fifth, A4 and the mic.
Just and equal tuning, in cents
A cent is a hundredth of a piano semitone, so the piano's intervals are whole hundreds. A pure interval is a simple ratio, and its size is 1,200 times the base-2 logarithm of that ratio: a fifth, 3:2, is 702.0 cents. Here is every pure interval Stackapella tunes to, against the piano.
These are 5-limit ratios, plus 7:4 for the barbershop seventh and 7:5 for the tritone of a diminished chord. Writers on just intonation don't all agree on every ratio: a minor seventh can also be 16:9 (996.1 cents), and a tritone 45:32 (590.2 cents).
| Interval | Ratio | Just | Piano | Off by |
|---|---|---|---|---|
| Minor second | 16:15 | 111.7 | 100 | +11.7 |
| Major second | 9:8 | 203.9 | 200 | +3.9 |
| Minor third | 6:5 | 315.6 | 300 | +15.6 |
| Major third | 5:4 | 386.3 | 400 | -13.7 |
| Perfect fourth | 4:3 | 498.0 | 500 | -2.0 |
| Tritone (diminished chord) | 7:5 | 582.5 | 600 | -17.5 |
| Perfect fifth | 3:2 | 702.0 | 700 | +2.0 |
| Minor sixth | 8:5 | 813.7 | 800 | +13.7 |
| Major sixth | 5:3 | 884.4 | 900 | -15.6 |
| Barbershop (harmonic) seventh | 7:4 | 968.8 | 1000 | -31.2 |
| Minor seventh (minor 7th chord) | 9:5 | 1017.6 | 1000 | +17.6 |
| Major seventh | 15:8 | 1088.3 | 1100 | -11.7 |
The three chords, tone by tone
Each tone is measured from the root, which the drone holds at the piano's pitch, so the root is the zero.
Major: the third sits 13.7 cents below the piano and the fifth 2.0 above. Minor: the third sits 15.6 above and the fifth 2.0 above. Barbershop seventh: the third 13.7 below, the fifth 2.0 above and the seventh 31.2 below.
So in a major chord the third comes down, in a minor chord it goes up, and in a barbershop seventh the seventh comes down most of all. The tiles under the meter show the same numbers.
Hearing it: beats
Two notes a little out of tune beat: a wobble in the sound, faster the further apart they are. A piano's major third on middle C beats about ten times a second; sung pure, the beats stop.
So listen as well as look. As you move toward pure, the wobble against the drone slows, and when it stops the needle sits in the green. Tap a tile first to hear where the tone belongs. It works the same for any instrument that can bend its pitch, like a violin, a trombone or a clarinet, played in a voice's range.
Tuning in a choir or a quartet
Tune to the bass and the chord, not to each note's piano pitch: the root first, then the fifth, the third and the seventh. In barbershop, most leads keep the melody close to the piano's tuning, and the other three parts tune pure around it.
This tuner checks one voice against a held root, not four singers at once. Use it to learn where each tone of the chord sits, then take that ear to rehearsal.
Free tools by Stackapella
You heard a chord lock. Now be one voice in it.
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 just intonation?
Tuning each interval to a simple ratio of frequencies: 3:2 for a fifth, 5:4 for a major third, 7:4 for the barbershop seventh. The notes' overtones then line up, so a held chord sounds still and full instead of wobbling. It's what singers and string players often reach for when they tune a chord by ear.
What is the difference between just intonation and equal temperament?
Equal temperament, the piano's tuning, splits the octave into 12 equal semitones of 100 cents, so every key sounds alike but only the octave is pure. Just intonation tunes each interval to its ratio, so chords ring, but a note's pitch depends on the chord it's in. The gaps are small but you can hear them: a just major third is 13.7 cents lower than the piano's.
How many cents is a just major third?
386.3 cents, which is 13.7 cents lower than the piano's 400. Its ratio is 5:4. Pick Major here and the Major 3rd tile shows the same 13.7 cents below the piano.
Why do barbershop singers lower the seventh?
To tune it as 7:4, the harmonic seventh, 31.2 cents below the piano's minor seventh. At that pitch it matches an overtone of the root, so the seventh chord rings instead of beating. Pick Barbershop here, then tap the 7th tile to hear it, and sing it.
What does ringing a chord mean?
When the voices are tuned pure, the beats between them stop and their overtones reinforce each other, so the chord sounds fuller and still. Barbershoppers call it ring or lock, and some hear an extra, higher note in it. This tuner says Ringing when you hold within 6 cents of pure, the same line our Barbershop course uses.
Should a choir sing in just intonation?
On held chords sung a cappella, leaning toward pure helps them ring. With a piano playing, match the piano, because a pure third against its equal third will beat. In practice no group holds one fixed just scale through a piece: singers adjust each note to the chord it's in, by ear.
Why do choirs go flat?
Often from tiredness, breath, or intervals sung carelessly, such as semitones made too wide on the way down. Tuning can add to it: a chain of chords each tuned pure to the last can drift by a comma, about 21.5 cents, before it comes home. Directors check by sounding the starting pitch again at the end.
What is a cent in music?
A hundredth of a piano semitone, so an octave is 1,200 cents. Cents measure small differences in pitch the same way at any height, which is why tuners and the table on this page use them. A pure interval's size in cents is 1,200 times the base-2 logarithm of its ratio.
Do I need headphones?
They help, but you can start without. The drone plays through your speaker, and the tuner asks your browser to take that sound back out of the mic, so it hears you. If the reading jumps about or seems to follow the drone, put headphones on or turn the drone down in More.
Is my voice recorded?
No. The microphone opens when you tap Start the drone, your pitch is worked out on this device, and nothing is recorded, kept or sent. Your root, chord and settings stay on this device.
More free tools
No account, no ads. Each one keeps working offline once you've opened it.
See all 17 tools