Device for actively reducing sound transmission, and panel comprising such device

A device for actively reducing sound transmission, provided with a first and second wall ( 3, 5 ) enclosing an inner space ( 1, 2 ), wherein at least the second wall ( 5 ) is provided with actuators ( 6 ), for instance eletromagnetic actuators and/or piezoeleteric elements, wherein the said inner space is provided with at least one inner wall ( 4 ) to divide this space into at least two layers of air ( 1, 2 ), which inner wall ( 4 ) is arranged such that the layers of air ( 1, 2 ) are in fluid connection with each other.