This paper presents a dual AC-3 and MPEG-2 audio decoder which can decode both bit-streams. MPEG-2 synthesis filtering is modified by the 32-point FFT to share the common data path with the AC-3's. The architecture of the decoder consists of a programmable DSP core and a hardwired common synthesis filter. The DSP core was designed suitable for audio processing. The common filter design adopts the suggested MPEG-2 modified synthesis filtering. The proposed system was synthesized with 0.6 /spl mu/m technology and proven to be cost-effective.