I had something making a loud sharp continuous 16 KHz tone in my house in the living room, at least according to an audio spectrum analyzer app.
I'm old enough that 16 KHz is outside my range so it never noticeably physically bothered me. I don't remember for sure, but I think I tracked it down to my TV.
That TV died a few weeks ago and I replaced it. I just checked, and there is no more tone.
Was this old enough to be a CRT TV? Their flyback transformers [1] very often emit a sound of 15.6 kHz, which is very obvious to all younger people and unnoticeable for older folks. I feel I was especially susceptible to this noise, and would frequently change rooms to escape it if the TV was on.
I whole-heartedly welcomed the change to flat TVs and monitors.
I'm old enough that 16 KHz is outside my range so it never noticeably physically bothered me. I don't remember for sure, but I think I tracked it down to my TV.
That TV died a few weeks ago and I replaced it. I just checked, and there is no more tone.