A method and a system for the active reduction, at a predetermined area, of the energy of a sound signal (dk(n)), also called a diffused noise signal, generated at the area by a primary signal (xk(n)), or noise signal, by the emission of a plurality of counter-noise signals (yk(n)) having an effect antagonistic to the diffused noise signal (dk(n)), each of the counter-noise signals (yk(n)) including a feedback counter-noise signal (yfbkk(n)) and a feed-forward counter-noise signal (yfwdk(n)). The method includes detecting the periodical components of diffused noise signal (dk(n)) for adjusting the feedback counter-noise signal (yfbkk(n)), and modelling the inverse of the secondary path for adjusting the feedback counter-noise (yfbkk(n)) and feed-forward counter-noise (yfwdk(n)) signals. The invention can be implemented to any type of industrial or non-industrial noise and in any location such as working places and relaxation places.