Pa subwoofer principle passive woofer size 15 inch design 1 way system speaker lf 1x 15 dimensions 470 x 600 x 410 mm weight 17 kg power rating rms 500 watts power handling peak 1 000 watt noise level 93 db impedance 8 ohm frequency response 35 3500 hz types of connection 6 35mm trs screw terminal speakon case material bass reflex