Considerations on Large Applications of Active Noise Control, Part II : Experimental Results

This paper treats the practical aspects of the prediction, implementation and verification of an active noise control system. The system was implemented in a mock-up of a Saab 340 propeller aircraft. A search algorithm, based on simulated annealing using the metropolis sampler was used to determine the positions for the control sources and sensors. The sound field was generated by a specially designed noise simulation system, using 12 individually controlled loudspeakers and a DSP--based signal generator. A version of the individually normalized complex lms algorithm was implemented for the control of the sound field. The prediction and verification of the active control system, was made in 20 evaluation positions, distributed at ear level above the seats. This is the second paper in a series of two, concerning the preparation, selection and verification of an active noise control system. Part I contains a theoretical treatment with some general guidelines for the implementation. Paper II is focused on the practical aspects of the implementation and verification.