Bookshelf speaker satellite speaker series dali zensor system 2 way system principle passive frequency response 62 26500 hz sensitivity 84 dbmw noise level 103 db impedance 6 ohm crossover frequency 2000 hz recommended amplifier power 40 125 power supply passive colour white housing surface veneer vinyl speaker enclosures bass reflex removable speaker cover number of tweeters 1 treble chassis 25 mm tweeter material tweeter tissue twee