While there are a few rooms that may be noisy due to location, the only time we've had a problem, it has come from noisy guests...which, of course, can't be predicted. Some people insist on being loud in the halls, or allowing their children to scream up and down the halls.
DCL does attempt to control this (asking for quiet in the Navigator, sending requests to offending cabins if they can be identified)...and even offering to move you due to an excessively noisy neighbor. Fortunately, that experience represents one out of our 10 cruises, but has taught me not to worry about "room noise" beyond avoiding being under the clubs!