Here is a May 2011 post of someone who discovered that: https://www.halloweenforum.com/threads/interesting-fact-about-flickering-led-candles.104046/ https://www

Here is a May 2011 post of someone who discovered that: https://www.halloweenforum.com/threads/interesting-fact-about-flickering-led-candles.104046/ https://www.halloweenforum.com/threads/interesting-fact-abou... And here is someone who recorded audio samples (no idea of the year): https://www.instructables.com/How-to-Listen-to-Light/ https://www.instructables.com/How-to-Listen-to-Light/ Edit: and here is maybe the video you were remembering: a video from June 2011 of someone hooking a speaker to listen to the flickering led: https://youtu.be/753-lkao8l0?si=-WqRRuBH644oKTXG https://youtu.be/753-lkao8l0?si=-WqRRuBH644oKTXG But they don't realize this may be an audio chip as the tune isn't really nice or recognizable.