An Air Canada Rouge Airbus A319-100, registration C-GBHZ performing flight RV-1803 from Kingston (Jamaica) to Toronto,ON (Canada) with 141 people on board, was enroute at FL340 near Nassau (Bahamas) when the flight crew noticed abnormal vibrations and noise in the cockpit, a few minutes later a pop was heard followed by smoke coming from the center pedestal, an ECAM message followed about 15nm north of Nassau. The crew worked the related checklists, declared emergency and diverted to Nassau for a safe landing. The Canadian TSB reported maintenance replaced a defective avionics blower fan