Bookshelf speaker series canton gle power rating 70 watt effective output 130 watt system 2 way system principle passive frequency response 42 30000 hz sensitivity 86 dbmw impedances 4 6 8 ohm crossover frequency 3200 hz power supply passive colour black cabinet surface ash housing material mdf enclosure speaker enclosures bass reflex removable speaker cover number of tweeters 1 treble chassis 25 mm tweeter material tweeter tissue num