C4W4 high-pitch whistling on all videos

Wasn’t able to edit my other feedback post on C4W3 whistling, so created another.

It’s occurring in all videos from 1 minute into the first and throughout except for final ‘recap and farewell’ video, so all are whistling except where the lecturer is visible in the video (so presumably this is down to using a different recording device).

Please reply if you are still observing this issue. I’ll request the staff to fix this.