I note that I hear the noise when I push one particular quadrant of the cone.
I just want a fucking replacement driver.
I feel your pain.
Since you hear the noise when one particular quadrant of the cone is pushed, it is possible the frame has bent, if the driver uses a stamped steel frame, twisting one of the spokes may cure it. Aluminum spokes tend to break rather than bend.
Set a sine wave to the frequency that makes it buzz the worst, then twist with a big wrench or channel locks.
Have fun, good luck.