I've done a bit more research and have come across some info indicating that tinnitus could be caused by certain kinds of head trauma. It got me thinking. In mid November my wife and I went to the Philadelphia Kimmel Center to hear some jazz. As I'm pretty sure I recollect, on the way home I did not have any ringing in my ears. Just a short time after than I slipped and hit my head on a closet door. I passed out for only a few seconds, and had no bump on the head (the door fortunately popped open when I hit it, relieving some of the force). At the start of the year and our next visit to the Kimmel, it was the first time I noticed ringing as we were on our way home. Is it possible this could be causing my problem?