might the buzzing sound simply be a misaligned diaphragm voice coil (vs. actual
mechanical damage)? the procedures for installing new diaphragms suggest that some
"5lb alignment tool" tweaking is the norm. Mostly curious, as diaphragms I've installed
have passed through the suggested sweep without issue thus far (properly cleaned and
gaps checked, etc...), but I don't have experience with newer JBL compression drivers.

If I followed right (no guarantee there), JBL is or will be looking at the unit in question?
It would be nice if they also provided a diagnosis of the "failure".

-grumpy

edit: or just being used outside design/intended range...as suggested.