Real-Time Frequency Detector

The tool detects frequencies from approximately 20 Hz to 20,000 Hz — the full human hearing range. For very low frequencies below 50 Hz, switch to FFT size 16,384 for better accuracy. The circular gauge uses a logarithmic scale to visualize the full range clearly.

Use the 🎤 Microphone dropdown to select the correct audio input device. If your microphone isn't listed, check Windows Sound Settings (right-click the speaker icon → Sound settings) and ensure your mic is enabled and set as default. You can also select "Stereo Mix" to analyze audio playing through your speakers.

The tool uses FFT (Fast Fourier Transform) to decompose the audio signal into individual frequency components. It identifies up to 5 strongest peaks in the spectrum, filters out harmonically-related duplicates, and displays each as a separate frequency with its note name and relative amplitude. This lets you see individual notes within a chord or identify multiple sound sources simultaneously.

Absolutely! Play a single string or note and watch the Pitch Accuracy meter. A centered needle (0¢) means perfectly in tune. You can also change the Tuning Standard — set A4 to 432 Hz for alternative tuning, or any value between 400–480 Hz. The cents display is color-coded: green (±5¢) = in tune, yellow (±20¢) = close, red = needs adjustment.

The Sensitivity slider sets the minimum signal threshold (in dB). Signals below this level are ignored as background noise. Slide left (e.g., −80 dB) to detect very quiet sounds; slide right (e.g., −20 dB) to suppress ambient noise and only detect loud, clear sounds. The default (−55 dB) works well for most environments.

❄️ Freeze pauses the display on the current reading so you can study it without it changing. 📋 Copy Reading copies the current frequency, note, cents, volume, and tuning to your clipboard. 💾 Export CSV downloads your entire session's history log as a spreadsheet-compatible CSV file — ideal for research, documentation, or trend analysis.

Yes! The tool works on iOS Safari 14+ and Android Chrome/Firefox. On iOS, you'll need to tap "Start Listening" to activate audio processing (Apple requires a user gesture). For best results, move your phone close to the sound source. All features including the gauge, multi-frequency peaks, and export work on mobile.

Your audio is 100% private. All frequency detection, analysis, and visualization happens entirely in your browser using the Web Audio API. No audio data is ever recorded, stored, or transmitted to any server. The tool works completely offline once loaded — you can even disconnect from the internet and it will continue to function.

The fundamental frequency of a typical speaking voice ranges from 85 Hz to 255 Hz. Men average around 85–180 Hz, women around 165–255 Hz. Singing voices extend further: a bass singer reaches down to ~82 Hz and a soprano can reach up to ~1,050 Hz. The detector will show the fundamental pitch — hum a steady note to see your exact voice frequency.

Concert A, also called A440, is the note A4 at exactly 440.000 Hz — the international tuning standard (ISO 16). It is the reference pitch used by orchestras worldwide. Some ensembles tune to A432 or A415 (Baroque pitch). Use the Tuning (A4) field to set your reference pitch and the tool will adjust all note calculations accordingly.

The 🎯 Calibrate button samples 1.5 seconds of ambient noise from your microphone and automatically sets the Sensitivity threshold to just above your noise floor (90th-percentile level + 6 dB margin). This eliminates false readings from HVAC, traffic, and background hum without you having to manually adjust the slider. Click it while the room is quiet before you start playing or singing.

The Detection Confidence bar shows how certain the algorithm is about the detected pitch. Green (≥70%) = reliable, yellow (40–70%) = moderate, red (<40%) = uncertain — the reading may be noisy or ambiguous. The Pitch Trend chart shows your pitch over the last 4 seconds as a rolling line graph, letting you see vibrato, portamento, or gradual pitch drift that you'd miss from a single Hz reading.

Yes — Space toggles Start/Stop, F toggles Freeze/Resume, R resets the session statistics and history, and C triggers the Auto-Calibrate noise floor sampling. Shortcuts work when the page is focused but not when you're typing in an input field.

Use the 🎤 Microphone dropdown and select "Stereo Mix" (Windows) or "What U Hear" — this routes your system's audio output back as a microphone input, letting you analyze music, YouTube videos, or any app's audio without a physical mic. On macOS, you may need a virtual audio driver such as BlackHole or Loopback since Apple does not expose system audio as a standard input. On Windows, enable Stereo Mix in Sound Settings → Recording devices if it is hidden.

A cent is one hundredth of a semitone — the smallest unit used in equal-temperament tuning. 100 cents equals one semitone, 1200 cents equals one octave. The Cents Offset shown by this tool is how far your note deviates from the nearest equal-temperament pitch. Within ±5¢ is considered in tune for most instruments; ±15¢ is still acceptable for casual playing; anything beyond ±25¢ will sound noticeably off in an ensemble. String players and vocalists routinely adjust a few cents for expressive intonation — the tool shows the raw deviation so you can decide.

For steady, clear tones, accuracy is typically within ±1–2 Hz (using parabolic interpolation at 48 kHz / 8,192-point FFT). A dedicated hardware chromatic tuner or strobe tuner can achieve ±0.1¢, which this browser tool cannot match due to microphone frequency-response limitations and browser audio pipeline latency. For casual tuning, checking vocal range, verifying a calibration tone, or educational use, the accuracy is more than sufficient. For professional instrument setup or scientific measurement, a calibrated hardware reference or a dedicated DAW with a high-quality ADC is recommended.