Hi Jared,
Good luck finding a replacement driver.
But if your search comes up empty, and your willing to try a little DIY repair, I may be able to shed some light on the subject.
Planar units of this type use some sort of plastic film to which is bonded an etched Aluminum conductor.
The two connection points of this diaphragm to the solder lugs or spade connectors is most likely the source of a bad connection causing the crackling you speak of. I have never seen this driver so I cant say for sure. I am sure they are produced in such a way that opening the metal casing will not be possible without some minor demolition of the casing.
I have no idea as the chance of a successful repair having never seen the unit, but if its shot already , what do you have to lose ?
If your interested in tackling this project you can email me pics of the back of the driver. I could give you a better idea on how to proceed.
Greg