Tom Scott
3 HN recommenders · recommended in 7 months, 2022–2025
5:31 · 5.8M views · Dec 20, 2021
Tom Scott explains Electrical Network Frequency analysis, where hum from the power grid in a recording is matched against grid logs to date and place it. He talks to a researcher and sets them a challenge.
The go-to short, accessible explainer for mains hum forensics, linked whenever recording authenticity or timestamps come up.
8 comments from Hacker News
If this is interesting to you or your kids, here's a less detailed but pretty accessible video [1] explaining how mains hum forensics work, complete with British accent. [1] this video
If you haven't already seen tom Scott's video on background noise giving the location of a recording due to power line frequencies being subtly different I recommend it. this video
A video on the same subject: this video I really enjoy Tom Scott. Everything he puts out is wonderfully concise.
I'm writing a open-source library ( [LINK] ) and a webapp ( [LINK] ) that detects the Utility Grid noise emitted by electrical devices (A/C, motors, appliances ...) from Video/Audio recording. It then tries to date the recording by matching it to historical data. The signal processing part is getting decent. I'm still trying to collect more reference signals in RU, UK, China and Japan. Tom Scott made a video about the idea: this video
Probably not practical but there was an interesting video by Tom Scott where investigators used the electrical hum background noise to determine when something was recorded. Maybe there is a way to audio record something to prove location. this video