The equipment support analog channel 16 and 1 USB extended recording channels, high-quality 21 pre amplification circuit, DSP processing bus structure, built in function of feedback canceller, noise canceller, the echo canceller etc., reducing quality sound, is mainly used in various kinds of large sites, can satisfy the application requirements of theatre, music hall, remote video conferencing, gymnasium, Chapel, conference centers, theme parks and other public sound reinforcement system etc.