What was found
WHILE CLIMBING THROUGH APPROX FL310, A LOUD REVERBERATING/THUMPING NOISE WITH CRACKLING STATIC NOISE BEGAN EMANATING FROM RT FWD CABIN INTERIOR SIDEWALL. ALSO A VIBRATION & WARMTH COULD BE FELT ALONG INTERIOR WALL. DIVERTED TO KBIL. NOISE CONTINUED AFTER ENG & APU SHUTDOWN, BUT STOPPED IMMEDIATELY WHEN BATTERIES TURNED OFF. ARFF FLIR ALSO SHOWED WARMER TEMPS IN AREA DESCRIBED. REMOVED RT INTERIOR PANEL TO GAIN ACCESS INSPECTED WIRING OF SPEAKERS & CONDITION OF SPEAKERS. OPS ENTERTAIN SYS FOR 1.5 HOURS TO DUPLICATE NOISE & HEAT. NO ABNORMAL NOISE OR HEAT SPOTS FOUND. REINSTALLED RT INTERIOR PANEL. SYSTEM OPS CHKD GOOD, ALL WORK IAW SMM 25-26-11 AND SMM 44-21-03.