What was found
AT APPROXIMATELY FL230 CLIMBING, ENROUTE TO FRG, EXPERIENCED TOTAL PASS OF COMMS WHERE BOTH SEATS AND BOTH RADIO 1 AND COULD NOT TRANSMIT AND/OR RECEIVE RADIO COMMUNICATIONS SQUELCH WAS INCREDIBLY LOUD AND EAR PIERCING. DID WHAT TROUBLESHOOTING THAT THEY COULD BEFORE SQUAWKING 7600. TURNED BACK TO SUA AND WAS ABLE TO ESTABLISH POOR COMMUNICATION WITH ATC, BUT ONLY FROM THE RIGHT SEAT. AN EMERGENCY WAS DECLARED. WENT INTO MX AND CND.