Rotor blade noise reduction system, fl ying object and noise reduction system

A rotor blade noise reduction system comprising:

• a plurality of rotor blades configured to be rotatable about a rotational axis;
• a plurality of first speakers disposed equidistantly on a first circumference which is opposed to one surface of a rotor blade plane defined by the rotor blades rotating about the rotational axis;
• a plurality of second speakers disposed equidistantly on a second circumference which is opposed to the other surface of the rotor blade plane;
• at least one evaluation microphone configured to acquire noise generated from the rotating rotor blades and control sound generated from the first speakers and the second speakers;
• and
• an active sound suppression processor configured to input a plurality of first delay control signals corresponding to the first speakers, and to input a plurality of second delay control signals corresponding to the second speakers.