Mutt-Well, I work for a big company that is fast making itself smaller and I have my own. You would not be getting the rantings of a private citizen. I am sure once my credentials are looked over you will have no doubts as to my background and abilities.
Michael B - I am at home and cannot give you exact levels. Mutt's look correct. Were you asking about a 747-200 or a -400? I can guarantee you that an old JT9D-7 will leave a lasting impression on what you think is noisey.
But, to answer your question.... The Large Antenov(spelling) family is probably louder. Though being Russian they are exempt from noise requirements. I think the EU is thinking that one over again though.
The big daddy of noise and is also exempt but path restricted ...... Drum roll........
CONCORDE @ 120 dB and I have seen LHR monitor data with it at 125 dB on takeoff. Good that it doesn't stick around long.