Floor speaker series auna linie 501 power rating 140 watt effective output 280 watt system 3 way system principle passive impedance 8 ohm power supply passive colour brown cabinet surface walnut housing material wood speaker enclosures bass reflex removable speaker cover number of tweeters 1 treble chassis 25 mm number of mid range drivers 2 midtone chassis 100 mm number of subwoofers 1 bass chassis 200 mm bass reflex port position rear firi