In applications such as modern school campus, prison, tunnels and factories, a flexible IP based system is required to address the needs of multiple independent sub-controls, individual broadcast of local message, frequent switching of zone assignment, time scheduled management and easy extension. MEGA IP based PA system is adopting standard TCP/IP platform and mature VoIP technology for extension and audio streaming. It features with powerful network audio matrix support up to 60 audio routing at the same time. With a PC based management system and IP audio terminals, multicast of audio in terms of play list broadcast, time schedule broadcast, zone broadcast can be made through user friendly interface and individual broadcast within each terminal, point to point intercommunication is achievable at the same time. It is a cost effective solution dedicate to a decentralized PA system.