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Vocal Formant Frequency Analyzer

Hold a sustained vowel into your microphone and watch its formant frequencies (F1, F2, F3) estimated live, plotted on a vowel-space chart with a nearest-vowel guess.

ℹ Formants are estimated with LPC (linear predictive coding) — an approximation of your vocal-tract resonances. Results depend on your voice, vowel, and microphone: children and higher voices have higher formants than the adult-average reference vowels shown. It works on steady vowels, not consonants or running speech, and isn’t a clinical tool. Your mic is analyzed live and never recorded or uploaded.

Microphone is off. Click “Start microphone”, then hold a vowel like “ah”, “ee”, or “oo”.

How It Works

A vowel’s character comes from formants — resonant peaks created by the shape of your throat, mouth, and lips. The tool reads a short slice of your microphone, runs linear predictive coding (LPC) to model the spectral envelope as a set of resonances, and reads the lowest peaks as F1, F2, and F3. F1 tracks how open your mouth is (higher = more open, like “ah”); F2 tracks front-vs-back tongue position (higher = more front, like “ee”). Plotting F1 against F2 places your vowel in the classic vowel space, and the nearest reference vowel is your closest match. Everything runs live on your device; nothing is recorded.

LPC is an estimate, not a measurement. The number of resonances it finds depends on the model order and your sample rate, and it can miss or merge formants on breathy, nasal, or quiet sounds. The reference vowels are adult-average values — your absolute formants scale with vocal-tract length, so a child’s or higher voice will read higher than the chart. Use sustained, clear vowels for the steadiest readings, and treat the vowel guess as a rough indicator.

Frequently Asked Questions

Is my microphone recorded or uploaded?
No. Audio is analyzed live in your browser and never leaves your device. Stopping the mic releases it immediately, and it’s released when you leave the page.
What are F1, F2 and F3?
They’re the first three formants — the lowest resonant peaks of your vocal tract. F1 and F2 mostly determine which vowel you’re making; F3 contributes to finer timbre and r-coloring.
Why don’t my numbers match the reference vowels?
The reference values are adult-male averages. Formant frequencies scale inversely with vocal-tract length, so women and children read higher. The pattern (relative positions) matters more than the absolute Hz.
Why do the numbers jump around?
LPC is sensitive to noise and pitch. Hold a steady vowel close to the mic in a quiet room. Consonants, whispers, and changing sounds won’t track well — it’s built for sustained vowels.
Can I analyze an uploaded file?
This tool is live-mic only. To inspect a recording’s spectrum, try the Audio Spectrum Analyzer; for pitch, the Pitch Detector.