This paper proposes a auditory system based on microphone array and composed of three parts: noise suppression, sound source localization (SSL) and beamforming. The ego-noise is harmful to the auditory system embedded in a small robot and very hard to be suppressed. We have proposed a method to design active acoustic metamaterials (AAMMs) that perform extremely well in the ego-noise suppression in a small robot. In this case, our research mainly focuses on the issues of reliability and real time on auditory system algorithms. A 2-stage SSL algorithm is adopted in our system to reduce the complexity. Furthermore, the matrix inversion can be processed in parallel with signal sampling, which means very low latency between the output and the input.