# Indicator relay sounds — provenance

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## Indicator relay recordings

The indicator's flasher relay (Gyan's ask 2026-11-02: "proper ticking sounds"): EngineAudio plays `tick` as the
lamp lights and `tock` as it goes out, on every edge of the blink (`state.indicatorLit`). Both are cut from the same
recording. All are real CC0 recordings from Freesound, played as recorded — only cut, mono and level. Loaded with
the drive voices (`prefetchIndicator()`).

| File | Source | Author | Licence | What it is |
|---|---|---|---|---|
| `tick-0.mp3` | [431816 — "Car blinker"](https://freesound.org/people/Audy_Leonard/sounds/431816/) | Audy_Leonard | [CC0 1.0](https://creativecommons.org/publicdomain/zero/1.0/) | An Audi A2's blinker (Zoom H4n): a clean modern car tick, quiet tock. (2.66–2.87 s; Gyan's pick 2026-11-02, A/B tick E) |
| `tock-0.mp3` | [431816 — "Car blinker"](https://freesound.org/people/Audy_Leonard/sounds/431816/) | Audy_Leonard | [CC0 1.0](https://creativecommons.org/publicdomain/zero/1.0/) | The Audi relay's release click. (3.06–3.27 s; Gyan's pick 2026-11-02, A/B tock E) |

Licence checked on each sound's Freesound page (all show "Creative Commons 0") when the A/B set was
made (design/…-ab/README.txt; the A/B sets are local only, never shipped).

**Edits made** (`sox` + `lame`, from each sound's Freesound HQ preview MP3; no pitch, EQ or other processing): each
click is cut out (10 ms before it, ≤ 200 ms), downmixed to mono at 44.1 kHz, 3 ms fade-in / 40 ms fade-out, the SAME
gain on the tick and its tock (the tick peaks at −3 dBFS, their real relative level kept), 96 kbps mono MP3.
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