DIAGNOSIS This is not normal operation. The Clean Base suction motor is either obstructed or the filter is clogged, causing it to work harder and louder.
FIX Remove the dust bin from the robot. Empty the Clean Base's internal dirt compartment. Remove the blue reusable filter from the top of the Clean Base. Tap it clean over a trash can, then wash it with cold water. Let it dry completely for 24 hours before reinstalling.
IF THAT DIDN'T WORK Check for an obstruction in the Clean Base's suction pathway. Remove the dirt compartment and visually inspect the plastic air channel leading to the motor for trapped debris like hair or twist ties.
HEADS UP Never run the Clean Base without its filter installed. This can permanently damage the suction motor and will not resolve the noise issue.