tony sayer wrote:
On a possibly related topic...I'm one of those people who, in the
past, have been plagued by the mysterious "drone" that most cannot
"hear". I haven't heard it since we moved house but it was real and
quite location dependant although not directional. I know it wasn't
actually audio because I couldn't measure or record it.



There was a "hum" which it seems a lot of people could hear in the mid
70's, sounded like a distant diesel engine though you could never
quite work out which direction it was coming from. There where some
articles in the papers for a while then all mention faded away...


Yes, that is the one. There were suggestions of tinnitus or other medical
problems in the media but I'm convinced it was a real phenomena. The
frustrating thing was that nobody else experienced it in/around our house.
Since we moved I have never heard it.