The Laboratoire d’Electronique Industrielle has realized an active noise controller. The system is designed to efficiently attenuate low frequency transformer noise where passive methods are either ineffective or tend to be very expensive. This paper describes an acoustic mapping experiment: two loudspeakers simulate a transformer, the noise is measured by a 15 microphones antenna and the DSP calculates an acoustic map with the beamforming method. Simulation and experimental results are presented.