All planes have weird noises to them... its all apart of being machines. The flaps on boeings to me have an iritating noise. I personally love the buzzing droan of the busses and the other airplanes like the 757, DC10, 747 etc... The avro has an odd noise when the flaps extend from 0-18 degrees and when they're being retracted through 18-0 degrees. It sounds like a dying dinosaur. It's just the aerodynamic principles in action between the wing and flaps. When one of the backup systems for one of the hydraulic systems is being tested and used while on the ground they call it the "mating whales" sound.

By the way, how did you know full thrust was being used? Unless the rwy is contaminated or the rwy is short, most planes never use full thrust.