Hard to describe it as a ringing. Its more like a very high radio frequency sound. It could be a beacon from the great ice ship or its a message from outer space that can’t be deciphered. Its always there like a steam radiator valve when it is hot. (Like there are some of you who might remember them? Probably not.)
Mine is like crickets on a summer’s night most of the time.
Then there are days when it’s like Gregorian chants or Mormon Tabernacle Choir singing the hallelujah chorus for hours in another room.................