Video surveillance system, which can provide real-time display of the monitored scene and video playback, has been employed in many areas including: commercial security, accident investigation, law enforcement and emergency response. However, audio which carries important information not available in video is usually not taken seriously and used effectively. In this paper, we develop an enhanced surveillance platform by introducing the low-power wireless audio sensor networks (WASNs). We can obtain more comprehensive and precise monitoring without the limitation of the line-of-sight and lighting condition. Moreover, this platform is designed and built for providing key support to varieties of applications. This article describes the platform architecture, including design, implementation, and performance. We describe the audio sensor platform which can deliver high-quality audio over sensor network by multi-hops with low power requirement. In addition, we present the multimedia synchronization mechanism in the heterogeneous network which is the foundation of applications in the proposed platform. Our experiments include an in-depth analysis of the bottlenecks within the platform as well as measurements for the various components.