Active control of scattered acoustic radiation: a real-time   implementation
  This paper presents an active noise control experiment designed to validate a real-time control strategy for reduction of the noise scattered from a three-dimensional body. The control algorithm relies on estimating the scattered noise by linear filtering of the total noise measured around the body; suitable filters are identified from off-line measurements. A modified Filtered-Error Least-Mean-Squares algorithm then leads to the adaptive filters which drive the secondary sources. The paper provides the numerical simulations using a Boundary Element Method which helped in designing a feasible experiment in an anechoic chamber with a limited number of control sources. Eventually a real-time pure-tone implementation with 14 ordinary loudspeakers and a large body is shown to yield on average a 10 dB reduction of the scattered noise at the error sensors, which is close to the optimum reduction predicted by the numerical simulations for the sensor arrangement. 
Emmanuel Friot (LMA), R\'egine Guillermin (LMA), Muriel Winninger   (LMA)