Having a suitable model is one of the most important steps in active noise and vibration control systems. There are many applications in which the derived numerical model does not show the system behavior appropriately. In such cases, obtaining a model using system identification methods can play a special role. To this aim, in this paper the problem of identification of a flexible plate which is attached to upper side of an enclosure is addressed. The frequency response of the plate is measured between the two specific points and the data are applied to the several subspace-based frequency domain identification algorithms with and without Instrumental Variable method. Since the real system, by nature, is stable and the models identified in all cases are unstable, in the next step stabilization algorithm with different initial values is used to extract the stable part of the system. Finally, the qualities of the stabilized identified models are evaluated by calculating the RMS error between the measured and identified models.