I've had my new UE55TU7100 55" TV for a little over a week and it's been driving the kids to distraction. It emits a very loud 18.1 kHz tone when the volume on the internal speakers is set to anything over 9. It can be heard all over the house (by the children - not me as it's too high pitched) regardless of the volume control setting and took us a while to track down where the noise was coming from.
Confirmed my suspicions with a spectrum analyzer app on my phone: TV volume 9 or below, noise disappears. 10 or above, it's there and very loud. According to the phone's mic it's about as loud as someone shouting in the same room, but us adults in the house can't hear it due to being such a high frequency. The tone seems to be just on or off. The volume setting seems to make no difference to the loudness of it, other that it turning on or off.
Can this be fixed with a firmware update or is it a hardware fault? Am I going to have to get an external amp & speakers?
We also have a pet hamster which has not been it's usual self since we got the new TV. I hope we've not driven it insane.