The noise you are referring to is just the sound all RB211's make on take off. I have been told by flight deck crew that its the sound of the tips of the fan blades travelling at supersonic speeds. I do agree that AD is slightly louder than the other 757's, but nothing overly noticeable. Some of the 737's are like that too.
Just for the record though, I think this is sound you are referring to:
http://www.flightlevel350.com/Aircra...ideo-4751.html