Note Detector
Use one clear voice or instrument note in a quiet room. Audio stays in your browser.
Session span describes detected pitches, including brief notes. It is not a comfortable singing-range or voice-type assessment.
Up to 20 MB and 180 seconds. MP3/WAV/OGG/WebM depend on browser decoding. Single voice/instrument only; chords are not transcribed. Selected audio stays in your browser.
Choose a recording to begin.
Notes held for at least 120 ms are grouped in time order. Staff placement shows pitch on a treble staff; this is not rhythmic notation, key detection or polyphonic transcription.
- Start microphone input or analyze a local file.
Settings & measurement notes
Microphone features need HTTPS and browser permission. Stop or hide/leave the page to release input. Reference tones pause measurement. Noise, harmonics and polyphonic sound can affect estimates.
A4 defaults to 440 Hz. An octave doubles frequency; twelve equal-tempered semitones make an octave.
Related tools
- Pitch Test — Compare detected singing with an explicit target note.
- Voice Frequency Test — Measure and interpret a short sample’s fundamental-frequency distribution.
- Song Key Finder — Estimate tonal key candidates from a local audio excerpt.
- Vocal Range Test — Find and record comfortable singing endpoints before choosing a related task.
Use the Note Detector to identify the pitch of one clear musical sound at a time. Sing a comfortable note into the microphone, or analyze a supported local audio file. The tool connects detected frequency with a nearest note name and helps you inspect short note events without treating the result as a complete musical transcription.
Find a note with your microphone
- Choose the microphone you intend to use and reduce competing sound.
- Start live detection and allow microphone access.
- Sing or play one steady note at a moderate level.
- Read the note, octave and frequency together.
- Repeat before relying on a brief or unexpected reading.
A single sustained sound is a useful first check. A chord, a recording playing behind your voice or several people singing together can produce ambiguous results. This detector follows a dominant repeating pitch; it does not separate every sound source.
The live search covers approximately 50–2,000 Hz. A frequency inside those limits is not guaranteed to produce a reliable estimate. Very quiet, irregular or noisy input can leave gaps.
Understand note names, octave numbers and cents
A note label includes a pitch class and an octave. C3 and C4 share a letter name, but C4 is an octave above C3 and has twice its frequency in equal temperament.
The nearest-note display rounds the detected pitch to an equal-tempered note. Cents describe the smaller distance from that reference. One semitone contains 100 cents; a positive offset is higher and a negative offset is lower than the selected reference.
For example, with A4 set to 440 Hz, an input at 445 Hz is approximately 19.6 cents above A4. The label can remain A4 while the cents value changes. That is why reading only the note letter loses useful information.
The A4 reference can be adjusted from 400 to 480 Hz. Use the same setting when comparing sessions or checking against another instrument. A reference change affects the musical interpretation of a frequency, not the sound already captured.
Analyze an audio file
Select a local file within the tool’s 20 MB and 180-second limits. MP3, WAV, OGG and WebM support depends on the browser and the codec inside the file. A file extension alone does not guarantee successful decoding.
Choose Mix, Left or Right when the recording contains different material in each channel. If a melody is isolated on one side, selecting that channel may make detection clearer. Mixing two different notes can make the task harder.
The browser also applies a decoded-sample limit. A file can meet the size and duration limits yet still exceed that processing cap. Use a shorter excerpt when the tool asks for one, preferably containing a single clear melody or held sound.
Read the note-event display
The tool groups consecutive detections into note events, retaining events that last at least about 120 milliseconds. A short transition may therefore be absent from the event list even when it appears briefly in the live reading.
| Display | Useful interpretation |
|---|---|
| Pitch trace | Recent movement in detected frequency |
| Note events | Grouped stretches of the same nearest note |
| Treble staff | Approximate musical pitch placement |
| Piano highlight | A keyboard reference within C1–C7 |
The staff is a pitch guide, not engraved sheet music with inferred rhythm, meter, rests and expressive markings. A keyboard highlight also does not prove that every component of a complex sound has been identified.
Check an unexpected octave
If your comfortable note suddenly appears one octave higher, listen and repeat. A strong harmonic can be mistaken for the fundamental. Background music, breath noise, microphone processing and an unstable onset can all affect tracking.
Try a plain vowel, keep the volume moderate and wait for the sound to settle. Do not force a lower or higher note to make the display agree with an expectation. Use reference playback to compare the perceived pitch.
For a longer frequency summary rather than individual note events, open the Voice Frequency Test. To compare a sung sound against an explicitly chosen note, use the Pitch Test.
Save a useful record
Copy the summary or download the available note-event CSV and analysis JSON. These exports describe measurements; they are not an audio recording, a MIDI file or a finished score.
Keep a brief note of the sound source, A4 setting and whether you used a microphone or a file. The same melody recorded with accompaniment may produce a different event list from an isolated vocal take.
Audio processing happens locally in the browser. Live analysis does not create a saved voice recording, and selecting a file for analysis does not upload it through this tool. Stop input when finished and save any measurement export you want to retain before clearing the session.
Frequently asked questions
Can this find a note from my voice?
Yes, it can estimate the nearest note for clear, single-pitch singing. Ordinary speech moves quickly and includes unvoiced sounds, so a musical note label may change rapidly or disappear.
Can it detect chords?
No. It is a monophonic pitch detector. Several simultaneous notes can confuse the estimate, and the tool does not provide a chord-name analysis.
Will it identify a song?
No. Note measurements are not a song-recognition database. The Song Key Finder estimates tonal key from a file, but it also does not identify a recording’s title.
Why is a fast note missing?
Events shorter than the grouping threshold may be excluded. A weak or irregular sound may also lack enough reliable pitch frames. The output should not be treated as a complete transcription.
Can I use detected notes for a range test?
They can help you recognize a pitch, but a full range result needs comfortable low and high endpoints. Use the Vocal Range Test to record those endpoints and calculate their interval.