Braat shows you, in real time, the pitch and resonance of your voice as you speak. It's a practice aid aimed at voice training — including trans voice training, where pitch (F0) and vowel resonance (F1-3) are commonly used reference points. It may also be useful for singing practice, accent work, or just exploring how your voice works.
Braat's signal-processing algorithms are adapted from Praat, a widely used tool in phonetics research. Praat is primarily oriented toward offline analysis; Braat takes its algorithms and runs them on a live microphone in the browser, with no install and no upload.
- Live spectrogram — your voice's frequency content as you speak
- Pitch (F0) tracking — Praat's filtered autocorrelation method
- Formant (F1–F3) tracking — Burg's method LPC, plotted on a vowel chart
- Voice activity detection — Silero VAD picks out voiced segments
- File import — drop in a recording and analyze it offline
- Private — audio stays in your browser; nothing is uploaded
- Offline — once loaded, works without a network connection
Braat uses AudioWorklet, Web Workers, and SharedArrayBuffer, which need a recent browser (Chrome, Firefox, or Safari).
Braat is alpha and in active development. Core features work, but expect changes to the UI and algorithms. A usage guide is planned but not yet written.
All audio processing happens in the browser. An AudioWorklet captures microphone PCM into a SharedArrayBuffer ring, and three Web Workers read from it in parallel:
- a spectrogram worker (FFT-based, with a Bark-scaled colormap),
- a formant worker running pitch (filtered autocorrelation) and formant (Burg LPC) analysis,
- and a VAD worker running Silero v6 via ONNX Runtime Web.
See CLAUDE.md for the architectural overview. DSP code ported from Praat is attributed in each source file's copyright header.
Source and issue tracker: https://codeberg.org/jocelyn-stericker/braat
Contributions — code, bug reports, or feedback from using it — are welcome.
Copyright (C) 2026 Jocelyn Stericker jocelyn@nettek.ca
This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License along with this program. If not, see https://www.gnu.org/licenses/.
This project contains code derived from Praat. That code is:
Copyright (C) 1992-2008,2011,2012,2015-2020,2022-2024 Paul Boersma
Copyright (C) 1993-2020 David Weenink
This project also contains a TypeScript port of the Bournemouth Forced
Aligner (BFA) for phoneme-level forced alignment, in
src/lib/alignment/.
The upstream BFA is:
Copyright (C) Tabahi tabahi@duck.com
The upstream BFA is licensed under GPLv3; this port is distributed under
AGPL-3.0-or-later. It runs the CUPE acoustic model via onnxruntime-web; the
model weights are not bundled. See
src/lib/alignment/README.md
and
ATTRIBUTION.md
for details.