Polyphonic tuner: all strings at once
A polyphonic tuner listens to several notes at the same time. Instead of plucking one string, waiting for the needle and moving on to the next, you strum all the open strings at once and see a list with one meter per string: which ones are in tune (green), which are flat and need tightening, and which are sharp and need loosening. It is the quickest way to check your instrument before you play, between songs, or after the heat of the stage has pulled the strings out of tune.
How to use it
- Tap Turn on microphone and allow access. Keep your phone or computer close to the instrument, ideally a hand's width from the guitar's sound hole or from the amp's speaker, in a room without talking or a fan running.
- Pick your instrument and tuning under Instrument and tuning. The tuner looks for exactly the notes of the tuning you choose.
- Strum all the open strings in one stroke, without fretting anything, and let them ring. In under a second every string gets its own meter: the number tells you how many cents it is above (+) or below (−) the target note.
- When the sound fades, the result stays frozen on screen. Adjust the tuning pegs that are outside the green: tighten the strings with a minus sign and loosen the ones with a plus sign.
- Strum all the strings again to check. The tuner measures every new strum on its own; the Measure again button clears the screen and waits for the next strum.
Help and explanations
It works with guitar (acoustic, classical or electric), 4-string bass, ukulele and cavaquinho, in standard tuning and in drop D, half step down, DADGAD, open G and open D. It runs in the browser on your phone or computer, it is free, there is no account, and the sound is analyzed on your own device, without recording or uploading anything. For a string that is way off, use a one-string-at-a-time guitar tuner first; the polyphonic tuner shines at the final check.
How a polyphonic tuner hears every string
A regular tuner looks for a single note and gets lost when six strings ring together, because the waves blend. A polyphonic tuner already knows which notes should be sounding (E2, A2, D3, G3, B3 and E4 on a guitar in standard tuning) and looks for each of them in the spectrum of the sound, the list of frequencies the microphone picks up. To see differences of a few cents on a low string, it analyzes about two thirds of a second of sound at once.
Each string rings with its fundamental note plus several harmonics (twice, three times, four times the frequency). The tuner measures the fundamental and the first three harmonics of every string and combines those readings, giving more weight to the strongest ones. This helps a lot on low strings, which phone microphones pick up poorly: on the guitar's low E, the second and third harmonics usually come through cleaner than the 82 Hz fundamental itself.
When it works well, and when it does not
The polyphonic tuner works best with the instrument close to the microphone, in a quiet room, and with the strings already close to pitch, within about a half step up or down. It looks for each string within 100 cents (a half step) of the expected note; a string further off than that can be mistaken for its neighbor or show up as “not heard”. In that case, tune string by string first with the guitar tuner, the bass tuner, the ukulele tuner or the cavaquinho tuner, and use the polyphonic tuner for the final check.
Some strings share frequencies with others. On a guitar, the 2nd string (B3) lands almost exactly on the third harmonic of the low E, and the 1st string (E4) lands exactly on its fourth harmonic. The tuner separates those notes mathematically, but with less margin: if you do not play the 1st or 2nd string, it may still show as in tune because of the 6th string's harmonic. In open tunings with three D strings (DADGAD, open D and open G), the D strings can pull each other's readings by a few cents. For fine tuning to ±1 cent, a one-string-at-a-time tuner is still more precise.
Tunings you can check
On guitar: standard (E2 A2 D3 G3 B3 E4), drop D (D2 A2 D3 G3 B3 E4), half step down (E♭2 A♭2 D♭3 G♭3 B♭3 E♭4), whole step down (D2 G2 C3 F3 A3 D4), DADGAD (D2 A2 D3 G3 A3 D4), open G (D2 G2 D3 G3 B3 D4) and open D (D2 A2 D3 F♯3 A3 D4). The numbers after the notes are octaves: E2 is the low E on the 6th string and E4 is the high E on the 1st.
On other instruments: 4-string bass (E1 A1 D2 G2), ukulele with the high G (G4 C4 E4 A4) and cavaquinho in D G B D (D4 G4 B4 D5). Under Settings you can change the reference A (440 Hz is standard), choose between C D E and Do Re Mi, and lower the sensitivity in noisy rooms.
Tips
- Strum with your hand still at the end of the stroke and without muting anything: a muted string disappears from the spectrum and shows up as “not heard”.
- An unplugged electric guitar is too quiet for the microphone. Plug it into the amp with a clean sound, no distortion or chorus, and keep the phone near the speaker.
- Always tune up to the note: if a string is sharp, loosen it slightly below the target and tighten it back up into the green. That way the string settles on the peg and holds its tuning better.
- After tuning with the polyphonic tuner, strum an open chord such as E major and check it with the chord identifier to confirm it recognizes the right chord.
Frequently asked questions
What is a polyphonic tuner?
It is a tuner that measures several strings at the same time. You strum all the open strings together and it shows the tuning of each one in a list, instead of asking for one string at a time. The idea became popular with stage tuner pedals; this one works in your browser with your device's microphone.
Does it work on my phone?
Yes. Open the page in Chrome, Safari, Edge or Firefox, tap Turn on microphone and allow access. Keep the phone about a hand's width from the instrument. On slower phones the readings take a moment longer to appear.
Do I have to strum every string?
To see all of them, yes. If you only play some, the others show as “not heard”. The exception is strings that coincide with harmonics of other strings, such as the 1st and 2nd strings of a guitar: they may show up even when you did not play them, so always strum all the open strings together.
Why does a string say “not heard”?
Because its sound was too weak or it is too far from the expected note (more than a half step). Strum a little harder, move the device closer and check that the selected tuning matches your instrument. If the string is way off, tune it first with a one-string-at-a-time tuner.
How accurate is a polyphonic tuner?
In tests with synthetic chords, readings land within about 2 cents of the true value; with a real instrument, room noise and a phone microphone, expect a few cents of wobble. Green means within ±5 cents, a difference very few people can hear. For setup work and fine tuning, use a one-string-at-a-time tuner.
Is the audio recorded or uploaded?
No. The microphone sound is analyzed on your device, inside the browser, and nothing is recorded or sent to a server.