Clefle
Credits
Clefle is built on the work of many people who shared it freely. Thank you.
Violin recordings
The ten violin samples come from VSCO-2 Community Edition by Versilian Studios (Sam Gossner) — solo violin, bowed with vibrato, played softly. The collection is in the public domain under CC0 1.0.
We trimmed each sample to 2.2 seconds and retuned the ones recorded slightly off pitch — the original middle C was 23.9 cents sharp — so the violin you hear in Clefle is in tune.
Fonts and music symbols
All three are licensed under the SIL Open Font License 1.1.
| Font | Used for | By | License |
|---|---|---|---|
| Bravura | Clefs, notes, accidentals | Steinberg Media Technologies GmbH | OFL 1.1 |
| Lora | Headings and large note names | The Lora Project Authors | OFL 1.1 |
| Be Vietnam Pro | Everything else | The Be Vietnam Pro Project Authors | OFL 1.1 |
The Lora and Be Vietnam Pro files are Google Fonts' own Latin and Vietnamese subsets, served unmodified. Bravura ships with the VexFlow library; the home page draws four of its symbols as shapes.
Open-source libraries
| Library | Used for | License |
|---|---|---|
| React | The app's interface | MIT |
| VexFlow | Drawing the staff | MIT |
| Tone.js | Playing the violin sounds | MIT |
| standardized-audio-context | Audio that behaves the same in every browser | MIT |
| ts-fsrs | The review schedule | MIT |
| Dexie.js | Storing progress in the browser | Apache 2.0 |
| Zustand | Session state | MIT |
| Workbox | Installing to the home screen | MIT |
The full license text and copyright notice for each library, including the packages they depend on, is in the library licenses file.
Methods
- Pitch detection: the YIN algorithm by Alain de Cheveigné and Hideki Kawahara (2002), running on your device.
- Review schedule: FSRS by Jarrett Ye and the open-spaced-repetition community.