What was found
CLIMBING THROUGH APPROXIMATELY 17,500 MSL A POPPING SOUND WAS HEARD, THEN THE CABIN ALTITUDE BEGAN TO CLIMB APPROXIMATELY 2000FT PER MINUTE. PROCEDURES IN THE QRH WERE COMPLETED BUT RESULTED IN NO CHANGE TO THE SITUATION. AN EMERGENCY WAS DECLARED AND THE DECISION MADE TO DIVERT. AN EMERGENCY DECENT WAS INITIATED, INITIALLY TO 15K FEET MSL, THEN DOWN TO 10K FEET MSL. THE CABIN ALTITUDE EVENTUALLY ROSE TO APPROXIMATELY 9500 FEET BEFORE LEVELING OFF. ATC PROVIDED VECTORS FOR THE RNAV/GPS APPROACH. APPROACH WAS CONDUCTED AND THE AIRCRAFT LANDED WITHOUT FURTHER ISSUE.