Originally Posted by
Chop61
When trying to pinpoint noise when the bike is on a repair stand, I'll use the empty spool from a roll of paper towels. I'll hold it up to my ear and point the other end to the part on the bike where I think the noise is coming from. It really does help, though it seems pretty stupid after typing it up here.
Another less embarrassing trick is to use a longer blade screwdriver. You put the blade on the part where you think the noise is, and your ear on the end of the handle. More accurate than your method, OTOH though, you want to be careful not to scratch what you put the blade end on, if visible scratches matter.