The present invention discloses a moving system (3) for a piezoelectric speaker (1), comprising a membrane (4) and a piezoelectric layer (5) attached thereto, wherein a movement of the moving system (3) in a main direction (MD) is substantially caused by dilatation/contraction of the piezoelectric layer (5) transverse to said main direction (MD). Accordingly, there is no translatory movement whenexciting the moving system (3), but only a bending movement. To provide an advantageous frequency response of the moving system (3), it is built up asymmetrically with respect to the moving characteristics. Accordingly, the modes are frequency shifted on the one hand and of less influence on the other. Hence, the frequency response of an inventive speaker (1) has less elevations and depressions in the frequency response. The concrete design of a moving system (3) is preferably done by the use of a computer simulation based on a finite elements method. In a preferred embodiment the local compliance and/or the shape of the moving system (3) is asymmetrical with respect to any point in the plane of the moving system (3).