Roland BA-330 PA System, Black All-in-one portable digital PA system suitable for use anywhere with powerful high-quality stereo sound for audiences of up to 80 people No setup required, just plug in and go! Powered by AC power or eight AA batteries. Four custom-designed 6.5" speakers and two tweeters for wide stereo projection with built-in effects: EQ, reverb, delay, and wide (on/off per channel) Four-channel configuration: two channels for mic/instruments plus two channels for stereo inputs, Stereo Aux input with dedicated volume-control knob Advanced Intelligent Anti-Feedback function