Same problem here. I'm pretty sure it's a hardware fault of the recent models. I had a 330 Hz buzz on mine. Matt Cadwell's video has a 430 Hz buzz. The difference might be to do with sampling frequency?
In July 2020 I tried 2 lifecams, and had to return both. I tried on a PC and a laptop, and at 2 different suburbs, to rule out ground loop, OS and environment issues.
I tried a friend's older model lifecam 3000 on my laptop and there was no buzz on it.
It's a real shame because the camera and mic quality are otherwise very good for the price. I'm really hoping a new batch corrects the issue, but i'm reluctant to buy without trying first. If you're buying this for camera only, and dont need audio, it's be fine.
I can absolutely second this. I bought a third webcam now, which was built 2046, and low and behold, same issue on 3 different computers. Desktop and Laptop. Hope they fix this issue at some point, as the webcam is otherwise very decent and worth its price.