Bookshelf speaker series q acoustics 3000 series system 2 way system principle passive frequency response 64 22000 hz sensitivity 88 dbmw impedance 6 ohm crossover frequency 2900 hz recommended amplifier power 25 75 power supply passive colour brown front colour black speaker enclosures bass reflex removable speaker cover number of tweeters 1 treble chassis 25 mm tweeter type tweeter calotte number of midbass drivers 1 bassmidtone chass