Note Identifier
Identify a Musical Note
Use your microphone to detect a sustained sung or played note in real time.
Audio is analyzed only in this browser and is not uploaded.
ā
Waiting for a stable note
Piano key
Recent notes
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Identify a Musical Note Online
The Note Identifier listens to a sustained vocal or instrumental sound through your microphone and estimates its musical note, octave, and frequency in real time.
It also shows the nearest equal-tempered reference frequency, cents deviation, flat/in-tune/sharp status, signal confidence, input level, tuning needle position, and the corresponding piano pitch class.
The tool is designed for one clear note at a time. It does not identify chords, transcribe melodies, analyze uploaded audio, or score singing ability. Microphone audio is processed locally in the browser and is not uploaded by the plugin.
How to Use the Note Identifier
Choose Your Microphone and Settings
Select an available input from the Microphone device menu. Use Refresh devices after connecting a USB microphone, audio interface, headset, or other input.
Before starting, configure these options:
| Setting | What it changes |
|---|---|
| A4 calibration | Sets the reference pitch from 430 to 450 Hz |
| Accidentals | Displays chromatic notes as sharps or flats |
| Noise-gate sensitivity | Controls how strong the input must be before detection |
The default calibration is A4 = 440 Hz, the common reference used for equal-tempered tuning.
The accidental preference changes only the note label. For example, the same pitch may appear as CāÆ or Dā.
Noise-gate sensitivity affects quiet-signal rejection:
- Low accepts quieter input.
- Medium is the default.
- High requires a stronger signal and can reduce background-triggered results.
Start Identifying Notes
- Select Start identifying.
- Allow microphone permission in the browser.
- Sing or play one sustained note.
- Hold the pitch long enough for the tool to report a stable result.
- Select Stop when finished.
For better detection, use a steady note without chords, backing music, speech, or heavy room noise.
Microphone access requires HTTPS or localhost in supporting browsers.
Play the Reference Tone
The Play reference tone button generates the currently selected A4 calibration frequency. With the default setting, it plays 440 Hz.
Changing the calibration to 442 makes the reference button play A4 at 442 Hz. It does not play the note currently detected from your microphone.
Understanding the Detected Note
Note Name and Octave
The main result uses scientific pitch notation, combining a note name with an octave number.
Examples include:
| Result | Meaning |
|---|---|
| A4 | A in the fourth octave |
| CāÆ4 | C sharp in the fourth octave |
| Dā4 | The same pitch class displayed as a flat |
| A5 | A one octave above A4 |
The piano display contains the 12 pitch classes from C through B. It highlights the pitch class of the detected note, rather than showing a full multi-octave keyboard.
Measured Frequency and Reference Frequency
The Measured frequency is the pitch estimated from the microphone signal.
The Nearest-note frequency is the calculated frequency of the closest equal-tempered note using the selected A4 calibration.
For example, with A4 calibrated to 440 Hz:
- A4 has a reference frequency of 440 Hz.
- A5 has a reference frequency of 880 Hz.
- A3 has a reference frequency of 220 Hz.
A measured pitch does not need to match the reference exactly. The difference is reported in cents.
Cents Deviation and Tuning Status
A semitone contains 100 cents. Cents provide a precise way to show how far the measured pitch is from the nearest note.
| Cents result | Plugin status |
|---|---|
| Below ā5 cents | Flat |
| ā5 to +5 cents | In tune |
| Above +5 cents | Sharp |
A result of ā12 cents means the pitch is below the reference note. A result of +8 cents means it is above the reference.
The tuning needle spans ā50 to +50 cents. Larger deviations remain pinned visually at the left or right edge, while the numerical cents output still reports the calculated value.
Confidence, Input Level, and Stability
Signal Confidence
Signal confidence indicates how strongly the microphone waveform resembles a repeating periodic signal.
The detector analyzes time-domain audio and looks for a repeating pattern. A clear, steady note usually produces higher confidence than breath noise, room noise, speech, chords, or a rapidly changing pitch.
Confidence is not a guarantee that the note name is correct. Strong harmonics can cause the detector to choose an octave above or below the intended fundamental.
Live Input Level
The input-level percentage represents relative digital signal strength. It is not a calibrated decibel measurement.
A stronger input can improve detection, but louder is not always better. Excessive gain may introduce distortion, while very low input may fall below the selected noise gate.
Use the sensitivity setting instead of moving unnecessarily close to the microphone.
Stable Note Detection
The plugin does not add every momentary reading to history. It waits for repeated detections of the same note with only small cents variation.
Once the note remains consistent across several analysis frames, the status changes to Stable note detected and the result is added to session history.
History stores:
- Note and octave
- Measured frequency
- Cents deviation
- Timestamp
The history remains only for the current browser session and can be cleared manually.
How the Pitch Detection Works
The detector uses a real browser-side pitch-analysis process:
- The browser requests a microphone stream.
- Echo cancellation, noise suppression, and automatic gain control are requested as disabled to preserve the rawer pitch signal.
- The Web Audio API supplies time-domain samples.
- An autocorrelation process compares the waveform with delayed copies of itself.
- The strongest repeating period is converted into frequency using the audio sample rate.
- The frequency is converted to the nearest equal-tempered MIDI-style note using the selected A4 calibration.
- The difference between measured and reference frequency becomes the cents deviation.
The analysis range is approximately 50 Hz to 2,000 Hz. Notes outside that range are not valid targets for this detector.
Best Uses for the Tool
Singing and Vocal Practice
Sustain one vowel at a steady volume and watch the note, cents, and tuning needle. Avoid sliding into the note while judging the final result.
Natural vibrato will make the cents value move. Focus on whether the reading remains centered overall rather than expecting it to stay at exactly zero.
Instrument Note Identification
The tool can identify single sustained notes from instruments such as guitar, piano, violin, flute, or other monophonic sources.
For plucked instruments, let the initial attack settle before reading the result. The attack can contain strong harmonics that temporarily confuse octave detection.
Why the Detected Note May Change
Unstable results usually come from one of these causes:
| Problem | Likely cause | Better approach |
|---|---|---|
| Note changes rapidly | Pitch is sliding or vibrato is wide | Hold a steadier tone |
| Wrong octave appears | A harmonic is stronger than the fundamental | Change microphone position or let the note settle |
| No result appears | Signal is below the noise gate | Use lower sensitivity or increase input slightly |
| Random notes appear | Background sound is triggering detection | Use higher sensitivity and reduce noise |
| Chord gives inconsistent results | Multiple pitches are present | Play one note at a time |
The detector is intended for one dominant periodic pitch. It cannot separate multiple simultaneous notes.
Accuracy and Limitations
The Note Identifier is useful for pitch practice, tuning checks, note recognition, and music education, but it is not laboratory measurement equipment.
Its result can be affected by microphone quality, room noise, distance, input gain, instrument harmonics, vibrato, and browser audio behavior.
It does not:
- Detect chords
- Name full melodies
- Accept audio uploads
- Correct pitch
- Measure vocal quality
- Grade singing accuracy
- Produce notation or sheet music
Frequently Asked Questions
What note am I singing?
Start the identifier and sustain one clear vowel. The tool displays the nearest note, octave, measured frequency, and cents deviation once it detects a stable pitch.
What musical note is 440 Hz?
With the default calibration, 440 Hz is A4. Changing the A4 calibration changes the reference frequencies used for all detected notes.
What do cents mean in pitch detection?
Cents measure the distance between the detected frequency and the nearest equal-tempered note. Negative values are flat, while positive values are sharp.
How close must a note be to count as in tune?
The plugin labels a pitch in tune when it falls between ā5 and +5 cents. Values below that range are flat, and values above it are sharp.
Why does the detected note keep changing?
The pitch may be unstable, too quiet, noisy, or mixed with other sounds. Hold one sustained note and adjust the noise-gate sensitivity if needed.
Why does the detector show the wrong octave?
A strong harmonic may be louder or clearer than the fundamental frequency. Let the note settle, change microphone position, or reduce brightness and background noise.
Can it identify guitar or piano notes?
Yes, provided you play one note at a time within the approximate 50ā2,000 Hz detection range. Short attacks may need a moment to settle before the displayed result becomes stable.
Can the Note Identifier detect chords?
No. It is designed for one dominant sustained pitch and cannot separate multiple simultaneous notes in a chord.
Is my microphone audio uploaded?
No. The plugin analyzes microphone audio locally in the browser. Session history stores only note results, frequency, cents deviation, and timestamps.