Note Detector
Sing or play a steady note to identify its pitch, frequency, octave, and tuning accuracy.
Detection settings
Start detecting
Microphone access requires HTTPS or localhost and your browser permission.
For best results, use a quiet room and hold one steady note.
Live result
Session insights
Recent notes
Detected notes will appear here.
Online Note Detector
Use the online note detector to identify the musical note you are singing or playing through your microphone. The tool shows the nearest note and octave, exact frequency in hertz, cents deviation, tuning status, detection confidence, session range, pitch stability, and recent note history.
All audio analysis happens locally in your browser. The tool does not upload or record microphone audio.
How to Use the Note Detector
- Choose your microphone or leave the default microphone selected.
- Set the A4 reference pitch. The standard setting is 440 Hz.
- Choose whether notes should appear as sharps or flats.
- Select low, medium, or high sensitivity.
- Optionally choose a target note for pitch-matching practice.
- Select Start detecting and allow microphone access.
- Sing or play one clear, sustained note.
The result becomes more reliable when the sound is steady. Rapid melodies, chords, background music, and strong room noise can make the detected note change frequently.
Use Copy result to copy the current reading. Select Reset session to clear the current range, stability, and detection statistics. Recent-note history can be cleared separately.
Detection Settings
| Setting | Default | What it changes |
|---|---|---|
| Microphone | Default device | Selects the audio input used for detection |
| Reference pitch | A4 = 440 Hz | Changes how frequencies are mapped to musical notes |
| Note spelling | Sharps | Displays notes such as F♯ instead of G♭ |
| Sensitivity | Medium | Controls the minimum input level required for analysis |
| Target note | None | Compares the detected pitch with a selected note |
The reference pitch can be adjusted from 415 Hz to 466 Hz. Most users should keep it at 440 Hz unless they are matching an instrument, ensemble, or tuning system that uses another reference.
The target-note selector includes notes from C1 through B7. When a target is active, the tool displays how many cents the detected pitch is above or below that target.
What the Note Detector Shows
The primary result is the nearest musical note, including its octave. For example, A4 means the A above middle C.
| Result | Meaning |
|---|---|
| Note | Nearest equal-tempered musical note and octave |
| Frequency | Measured fundamental frequency in hertz |
| Cents | Distance above or below the nearest note |
| Tuning | In Tune, Sharp, or Flat |
| Confidence | Reliability of the current pitch estimate |
| Target difference | Cents above or below the selected target note |
A positive cents value means the pitch is sharp. A negative value means it is flat. The plugin classifies a result within five cents of the nearest note as In Tune.
Reading the Tuning Meter
The tuning meter provides a visual version of the cents result:
- Left indicates flat.
- Center indicates in tune.
- Right indicates sharp.
A reading of -12¢ means the pitch is 12 cents below the nearest note. A reading of +8¢ means it is eight cents above it.
Confidence and tuning accuracy are different. A note can be detected with high confidence while still being sharp or flat. Confidence describes how clearly the tool identified the pitch, not how accurately the note was performed.
How the Note Detector Works
The detector analyzes microphone samples through the browser’s Web Audio system. It first measures the signal level and ignores audio that falls below the selected sensitivity threshold.
For a strong enough signal, the tool uses a YIN-style pitch-detection process to estimate the fundamental frequency. It compares delayed versions of the waveform, searches for a repeating period, and assigns a confidence value to the estimate.
Readings below the required confidence level are rejected. The plugin also ignores frequencies outside its supported 55–1760 Hz range.
To reduce flickering, it smooths recent estimates with a rolling median of up to seven frequency readings. It then converts the smoothed frequency to the nearest equal-tempered MIDI note using the selected A4 reference pitch.
The nearest note frequency is calculated from that reference. Cents deviation is then measured as the logarithmic distance between the detected frequency and the nearest note frequency.
The detector requires four matching stable frames before displaying a note as stable. This helps prevent short noises and unstable transitions from appearing as final results.
Understanding Session Insights
The plugin tracks additional information while the detector is running.
- Lowest note: The lowest stable note detected during the session.
- Highest note: The highest stable note detected during the session.
- Stability: A score based on the average absolute cents deviation collected during the session.
- Stable detections: The number of accepted stable readings.
- Recent notes: A session history containing note names and measured frequencies.
The stability score decreases as average pitch deviation increases. It is useful for comparing how steadily you held notes during the same session, but it is not a measure of vocal quality, musical ability, or voice type.
Recent-note history is stored in browser sessionStorage. It remains available during the browser session but is not uploaded to a server.
Practical Tips for More Stable Results
Use one sustained note at a time. This detector is designed for a dominant single pitch, not chords or full-song transcription.
Keep a consistent distance from the microphone and avoid singing directly into it at very high volume. Excessive input can distort the waveform, while very quiet input may fall below the sensitivity threshold.
Choose high sensitivity for a weak signal in a quiet room. Use medium or low sensitivity when background noise causes false detections.
Select the correct microphone before starting. Changing the device while detection is active requires restarting the detector.
Microphone access normally requires an HTTPS page or localhost. When no stable signal appears, check browser permission, device selection, room noise, and input volume before changing musical settings.
Common Misconceptions
The note detector does not correct pitch, generate tones, record performances, or upload audio files. It analyzes live microphone input only.
The lowest and highest session notes are not a formal vocal-range assessment. They simply report the lowest and highest stable pitches accepted during the current session.
Sharps and flats do not change the measured frequency. They only change the displayed name of enharmonic notes, such as F♯ and G♭.
Frequently Asked Questions
What note am I singing?
Start the detector, allow microphone access, and hold one clear note. The largest result shows the nearest note name and octave, while the frequency and cents values provide more detail.
What does the frequency result mean?
Frequency is the detected fundamental pitch measured in hertz. Higher frequencies correspond to higher musical pitches.
What do positive and negative cents mean?
A positive cents value means the note is sharp, while a negative value means it is flat. The farther the value is from zero, the farther the pitch is from the nearest note.
How close must a note be to count as in tune?
The plugin marks a reading as in tune when it is within five cents of the nearest note. Values outside that range appear as sharp or flat.
Why does the detected note keep changing?
The sound may be unstable, too quiet, noisy, or moving between pitches. Hold one sustained note, reduce background noise, and adjust sensitivity when necessary.
What does confidence mean?
Confidence estimates how strongly the analyzed waveform supports the detected pitch. It does not show whether the pitch is musically in tune.
What is the difference between confidence and stability?
Confidence applies to the current pitch estimate. Stability summarizes average cents deviation across accepted readings in the session.
Why would I change A4 from 440 Hz?
Change the reference only when matching an instrument or ensemble tuned to another standard. Altering A4 changes the frequencies assigned to every note.
Is microphone audio stored or uploaded?
No. Audio analysis takes place locally in the browser, and the plugin does not upload or record the microphone stream.
Can the detector identify chords?
No. It is designed to detect one dominant fundamental pitch at a time, so chords and overlapping voices may produce unstable or changing results.