# Sample audio attribution

The recordings in this directory are short excerpts of industrial and machinery
noise used as sample input for GramFrame. All four come from the
[Work With Sounds](https://commons.wikimedia.org/wiki/Commons:Work_With_Sounds)
collection on Wikimedia Commons and are licensed under
[Creative Commons Attribution 4.0 International (CC BY 4.0)](https://creativecommons.org/licenses/by/4.0/).
The licence was verified on each file's Commons description page (the
`{{CC-BY 4.0}}` permission template, backed by VRT permission ticket
2014082510012677) on the retrieval date given below.

Every file here has been changed from the original in the same way: a
30–45 s segment was cut from the recording, the audio was resampled to 16 kHz,
mixed down to a single channel, and re-encoded as 16-bit PCM WAV. No other
processing (filtering, normalisation, noise reduction) was applied.

## hot-bulb-diesel-engine.wav

- **Title:** WWS Hotbulbengineworking.ogg — "Hot bulb engine, working" (Pythagoras-Drott
  mechanical works, Norrtälje; large diesel-driven hot bulb engine built 1932,
  close-mic recording with the generator not running)
- **Author:** Work With Sounds / Torsten Nilsson
- **Source:** https://commons.wikimedia.org/wiki/File:WWS_Hotbulbengineworking.ogg
  (original at http://www.workwithsounds.eu/sound/hot-bulb-engine-working/)
- **Licence:** CC BY 4.0 — https://creativecommons.org/licenses/by/4.0/
- **Changes:** trimmed to 50–90 s of the original (40 s), resampled from
  44.1 kHz to 16 kHz, mixed from stereo to mono, converted from Ogg Vorbis to
  16-bit PCM WAV
- **Retrieved:** 2026-09-05

## icebreaker-ship-engine-room.wav

- **Title:** WWS IcebreakerKunashipsengine.ogg — "Icebreaker Kuna, ship's engine"
  (engine running in the engine room of the museum and training ship *Kuna*,
  Gorzów Wielkopolski, Poland)
- **Author:** Work With Sounds / Museum of Municipal Engineering
- **Source:** https://commons.wikimedia.org/wiki/File:WWS_IcebreakerKunashipsengine.ogg
  (original at http://www.workwithsounds.eu/sound/icebreaker-kuna-ships-engine/)
- **Licence:** CC BY 4.0 — https://creativecommons.org/licenses/by/4.0/
- **Changes:** trimmed to 80–120 s of the original (40 s), resampled from
  44.1 kHz to 16 kHz, mixed from stereo to mono, converted from Ogg Vorbis to
  16-bit PCM WAV
- **Retrieved:** 2026-09-05

## air-compressor.wav

- **Title:** WWS Aircompressormono.ogg — "Air compressor (mono)" (Atlas air
  compressor at the Pythagoras-Drott mechanical works, close-mic recording; the
  excerpt covers one load/unload cycle)
- **Author:** Work With Sounds / Torsten Nilsson
- **Source:** https://commons.wikimedia.org/wiki/File:WWS_Aircompressormono.ogg
  (original at http://www.workwithsounds.eu/sound/air-compressor-mono/)
- **Licence:** CC BY 4.0 — https://creativecommons.org/licenses/by/4.0/
- **Changes:** trimmed to 18–58 s of the original (40 s), resampled from
  44.1 kHz to 16 kHz (source was already mono), converted from Ogg Vorbis to
  16-bit PCM WAV
- **Retrieved:** 2026-09-05

## francis-water-turbine.wav

- **Title:** WWS FrancisTurbine.ogg — "Francis turbine" (water turbine used to
  generate electricity through hydropower)
- **Author:** Work With Sounds / Konrad Gutkowski
- **Source:** https://commons.wikimedia.org/wiki/File:WWS_FrancisTurbine.ogg
  (original at http://www.workwithsounds.eu/sound/konrad-gutkowski-3/)
- **Licence:** CC BY 4.0 — https://creativecommons.org/licenses/by/4.0/
- **Changes:** trimmed to 10–50 s of the original (40 s), resampled from
  44.1 kHz to 16 kHz, mixed from stereo to mono, converted from Ogg Vorbis to
  16-bit PCM WAV
- **Retrieved:** 2026-09-05