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 brown front colour black cabinet surface walnut housing surface veneer vinyl speaker enclosures bass reflex removable speaker cover number of tweeters 1 treble chassis