The QSC KLA181 Line Array Subwoofer is an 18" active subwoofer and is designed to compliment QSC's KLA12 2-Way Line Array Loud Speaker. The KLA 181 features an energy efficient 1000 watt power module. A polarity switch controls low frequency directivity and its pole receptacle is capable of mounting up to 2 KLA12 2-Way Line Array Loud Speakers. QSC's DEEP DSP algorithm provides extended bass by actively managing low-frequency transients. GuardRail protection circuitry prevents the amplifier module from unnatural and destructive clipping. An auto-standby mode will auto-engage after 5 minutes of inactivity to save energy. XLR and PowerCon input and thru connectors provide connection versatility, while a Phoenix connector allows daisy-chaining.