I was trying to pin down a suspected worn wheel bearing that is jut starting to get noisey using my Chassis Ear it occurred to me that rather than use the head phones I could just use an adapter to plug the output into the Aux port on the car stereo --- it worked altough still no clear cut diagnosis on the wheel bearing.
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)