one of the few things that suck about getting old - I didn't hear the high pitch in the previous video either but then I was an idiot and didn't protect my hearing at concerts or play music at reasonable volumes in my 20's. I now have a permanent mosquito alarm in my head at around the 13000-13500hz mark but I can't hear anything above that so the monitor hum was well out of range - Take care of your hearing indeed.