This runs formantwise 0.3 (the resonance engine) in your browser, still under active development. Questions and feedback welcome. The audio goes to the engine at its own sample rate, and the engine resamples anything faster than 24 kHz itself, exactly as the command-line tools do, so values match the command-line tools on the same file. Record the speaker anchor (F3/F4) with your results. Default TSV filenames contain it, and the JSON download holds the full requests and responses needed to reproduce a run.
1. Audio
Long recording, or audio above 16 kHz? Save a 16 kHz mono copy first.
Do this before anything else: a 16 kHz mono file uses far less memory in the browser (especially on phones) and gives the same analysis as the command-line tools run on that same file. Use it as the input for both. Resample audio files (in your browser; nothing is uploaded).
2. Intervals
3. Speaker
Blank = Auto: one prepass over the whole file sets the speaker anchor, and it is pinned on every measurement so all intervals share it. To use one anchor across recordings, load them together and Estimate, or paste values from an earlier run.
4. Measurement
Uses the engine's telephone profile, tuned for narrow-band phone recordings.
Frame-to-frame steadiness
Reading the engine's defaults...
Averages the spectral envelope over neighbouring frames before fitting (3 frames: 5 ms either side; 5 frames: 10 ms), so frame-to-frame noise does not move the fit. Applies to the measurements, not to the speaker estimate.
For each frame, picks among its candidate fits the one that keeps the formant tracks continuous, so a formant does not jump to its neighbour's slot (F2 read as F1) for a frame or two.
A running median of the fitted F1-F3 tracks over this window, after fitting. Use it for points well inside a vowel; turn it off for onset/offset and transition values or formant-dynamics work, where a smoothed value borrows from the neighbouring frames.
Comparison
Adds plain Praat To Formant (burg) F1-F4 at the same points, beside every result panel. It is computed in your browser by praatfan-gpl, a GPL-licensed reimplementation of Praat, loaded from its public host only when this is ticked and never part of this page (GPL-3.0).