Active Noise Control inside the Loadmaster Area of a Turboprop Transport Aircraft

The paper describes the design and test of a prototype active noise controller for a semienclosed cabin inside a turbo-prop aircraft. Here, the eight active noise control loudspeakers and sixteen microphones are mounted at the cabin walls and ceiling. For the development process, an acoustical mock-up is built to reproduce the acoustic situation inside the aircraft on the ground. The acoustic requirements on such a mock-up are described and wellfounded by a coupling analysis. Moreover, the controller is based on a frequency domain implementation of the steepest descent algorithm. To achieve the optimal performance and robustness requirements, a method to adjust the microphone and loudspeaker weights is presented. The new method also considers the uncertainty of the system in the controller parameter design process. Experimental results show the efficiency of the prototype system for a typical load case.