Subwoofer series heco victa prime power rating 100 watt effective output 200 watt system 1 way system principle active amplifier type digital cabinet surface ash housing material mdf enclosure control features adjustable transition frequency volume control switchable phase control design front firing subwoofer speaker enclosure bass reflex number of subwoofers 1 bass chassis 260 mm subwoofer material woofer paperkevlar width 318 mm height 450 mm