I can only speculate about
Videomaker – Learn video production and editing, camera reviews › Forums › Cameras and Camcorders › Other Camcorders › humming noise with Sony camcorders › I can only speculate about

I can only speculate about your TRV 82 but it certainly had to make some noise? Probably the newer camcorders make more noise because they cost less than the old models did, in inflation adjusted currency. They probably aren’t soundproofed as well as the old models? Since they are trying to make the new ones as small as possible, there probably isn’t any room for sound proofing?
I am amazed that the built-in Mic doesn’t pick up the noise and record it, if these things are making that much noise. As long as it is not being recorded, who cares how much noise it makes? I am sure you can get used to it? You will have to because there isn’t anything you can do to make them quieter.
Maybe I don’t understand what you are hearing? Why should using the LCD be any quieter than using the viewfinder? The only difference I can visualize is that you would hold the camcorder a little further from your ears? But the camcorder would still make the same amount of noise.
You might have too good of hearing? I served a few years in the US Army and the rifle and cannon fire ruined my hearing. I hear constant ringing and high frequency tones inside my head 100% of my waking hours. It is just something I have had to get used to. But maybe it masks the little things that annoy people that still have good hearing?
Dave