Pa sound system active speaker principle active power 800 watt woofer size 65 inch design 2 way system speakers hf 2x lf 2x 65 dimensions 298 x 288 x 695 mm weight 189 kg noise level 120 db impedance 4 ohm frequency response 55 20000 hz connections microphone sd card usb types of connection rcacinch stereo clamp contacts case material bass reflex