... .No noise protect function when power on, Low cut of the main channel music(20Hz-200Hz) The ... detecting fuctionOverload and short circuit protectingBBE effect output ON/OFF switchExternal jack of active subwooferProfessional digital key controlFull ... 5stepProtectionShort circuit current limited DC AC line fuse, thermal cut OFF, power up/down transients, slow artIndicatorsLCD+LEDCoolingVariable speed ...