In order to achieve real-time application of Active Structural Acoustic Control (ASAC) of coupled enclosure, the frequency independent ARMs are expected to disregard the change of Acoustic Radiation Mode (ARM) shapes with frequency and drastically reduce the computation costs for real-time applications. For regular coupled enclosure systems, such as rectangular plate-cavity system and cylindrical plate-cavity system with circumferential structural surface as elastic boundary, ARMs can be described as a subset of the cavity modes on the structural-acoustic interface, which makes them independent from frequency. However, for more complex coupled enclosure systems, the cavity modes in the structural-acoustic interface are not always orthogonal similarly and thus can’t be evaluated as ARMs of complex coupled enclosure.To sovle this problem, this paper proposes a wavelet-galerkin based method for obtaining frequency independent ARMs of complex coupled enclosure. The vibration on the elastic boundary and pressure in the coupled cavity are both expressed by Daubechies wavelet basis. After above procedures, the orthgonality of cavity modes in the structural-acoustic interface is always guaranteed again and they can be evaluated as ARMs complex enclosure as regular coupled enclosures. Therefore, the real-time application of ASAC of complex coupled enclosure can be achieved.