Loud Speaker Buzzing - Event Date: 16 May 2017

I'm a new registrant to the forum but have found every answer I've ever needed about my 2012 182G by scrolling through these threads.  Thank you to everyone that contributes!  This is a great resource!

I got in a hurry the other day and while putting the battery cables on in the dark, I crossed them.  The immediate sparks let me know what I had done wrong.  This blew the fuse for the battery converter, but the rest looked good. However the radio wouldn't come on.  After reading this forum, someone said their was an 'in line' fuse behind the mounted radio.  I took the four screws out of the radio mounting to the wall, and pulled it away from the wall. There was the fuse, and it was blown.  I replaced it and the radio came on immediately.  

I slowly began to put the radio back in place in the wall cutout when the inside speaker (only the inside one) started blaring a loud buzzing noise.

I've checked each of the quick connect wires on the wiring harnesses and everything looks to be connected.  Their are lots of mentions about poor grounding but I don't even know where the ground wire would be, and why would that be the problem when this has never done this before.

The buzzing is constant even when the radio is turned off in standby mode.   When the radio (Jensen AWM970) is on but at the zero sound level its buzzing but as soon as the volume is turned up to 1 or higher, the buzzing goes away.  As long as the radio or TV sound is on, their is no buzzing.

Any quick suggestions to what I may have done?