Point it at any sound and read the note live.
A detector is meant to stay on. Start it once, then run scales, arpeggios, or a full song and the note name refreshes with every sound you make. That live loop is what separates detecting from testing — you are not measuring one frozen note, you are watching the music move under your fingers in real time.
Point the same detector at a singing voice, an electric guitar, or a soft synth pad and it names the note either way. Buskers use it to find a key on the spot, producers use it to label a recorded take, and students use it to see scales light up as they play. One tool, every source.
A note detector is a pitch detector that never stops listening. The same autocorrelation engine estimates the fundamental frequency of each audio frame, but instead of checking one note on demand, the detector runs every few milliseconds and updates the displayed note name as the sound changes. That is what makes note detection feel live: you start it once, play a scale or a song, and the names light up in step with your fingers. The math is identical to a one-shot finder; the difference is that the detector keeps the loop open.
Because it reads continuously, a note detector is sensitive to how you attack and release notes. A clean legato run shows a smooth staircase of names; a hesitant start shows the detector hunting for the first stable pitch. Watching that behaviour is itself a lesson in phrasing, and players use it to hear whether their transitions are as smooth as they feel.
Different instruments feed the note detector very different waveforms. A flute is close to a pure tone and reads cleanly; a distorted electric guitar is thick with harmonics yet still resolves to the right note; a piano decays as it rings, so the detector tracks the pitch even as the loudness falls. A note detector handles all of them because autocorrelation keys on the fundamental period, not the brightness of the sound. Point it at a voice, a synth pad, or a brass instrument and the note name comes out the same.
The one limit is polyphony. A note detector follows the strongest pitch, so a single-line melody reads perfectly while a dense chord shows the most prominent note. For harmony you would need a full chord analyzer; for monophonic playing — solos, scales, vocal lines — the note detector is exactly the right tool.
Leave a note detector running during a practice session and it becomes a silent coach. Run an arpeggio and confirm every note appears in order; sing a phrase and see whether the detector agrees with the notes you intended. Teachers project it in lessons to demonstrate intervals live, and students watch scales appear under their hands instead of trusting memory. Because the note detector stays on through a whole song, it catches the spots you would otherwise skip past.
The leap a note detector gives you is continuity. A finder answers "what is this note?" one at a time; a detector answers "what notes am I playing, right now, all the way through?" That shift turns scattered checks into a flowing readout you can use to learn a tune, lock a key on stage, or label a take in the studio. Start it, play, and let the note names do the writing — the detector does the boring part so you can listen to the music.
The habit that pays off is leaving the note detector running while you actually play. Instead of stopping to check each note, start the note detector once, run your scales or a song, and glance at the names as they appear. You will notice a fingering that always reads a note late, or a vowel that pushes the pitch sharp, because the note detector shows the whole phrase rather than a frozen instant. Buskers use the note detector to find a key on the spot; learners use it to confirm a passage they are still memorizing. Keep it open and let the note detector do the watching while you make the music.
Common instrument landmarks at A4=440 Hz
| Note | Frequency | Description |
|---|---|---|
| C2 | 65.41 Hz | Drop-tuned bass C |
| E2 | 82.41 Hz | Lowest guitar string (E2) |
| C3 | 130.81 Hz | Bass open C (drop tuning) |
| A3 | 220.00 Hz | Guitar 5th-fret reference |
| C4 | 261.63 Hz | Guitar C at the middle |
| E4 | 329.63 Hz | Guitar high E open string |
| G4 | 392.00 Hz | Violin open G / guitar 3rd-fret G |
| A4 | 440.00 Hz | Violin open A, guitar 5th-fret A |
| C5 | 523.25 Hz | Flute / soprano sax comfort |
| E5 | 659.25 Hz | Violin E open string |
| C6 | 1046.50 Hz | Piccolo / top flute |
It is the live, always-on engine — the moment you make a sound it names the note, frequency, and tuning. Think of it as a pitch detector that stays running while you play.
A finder identifies one note you prompt it with; a detector stays on and chases the music as it moves, updating the note name with every sound. Use the detector for practising passages.
Yes. Point the mic at your phone, an amp, or a keyboard's speaker and it reads the note just as it would from live playing.
It tracks the strongest pitch, so a single-line melody reads cleanly. On a chord it shows the most prominent note — for full harmony you would need a chord analyzer.
Yes. It reads any pitch, fretless or not, and shows how many cents you sit from the nearest note.
Yes. 100% free, runs in your browser, and your audio is processed locally and never uploaded.
A note detector is the always-on ear at the end of your cable. The instant you make a sound it names the note, frequency, and tuning — point it at a guitar, a synth, or your own voice and the readout chases the music as you play. Teachers use it to demonstrate intervals live, players use it to find a key in seconds, and learners use it to watch scales appear under their hands. It runs entirely in your browser: nothing to install, nothing uploaded.
Pick your range and reference tuning and the detector ignores octave confusion, so what you see is the note you actually played — turn it on once and leave it running through a whole practice session.
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