The active bass-reflex subwoofer of the Quantum 720 range operates according to the downfire principle and is equipped with a 300 mm high-power long-throw woofer. Combined with the coated and hardened paper membrane, the Klippel-optimised magnet system not only provides for extreme depth, it also ensures the highest precision and structure in the bass range. Maximum operational safety and reliability is guaranteed by the ventilated high-performance voice coil. The amplifier located in the MDF enclosure with rounded sides delivers 180 watts of RMS power output as well as active frequency response equalisation up to 150 Hz. Two generously dimensioned Airflex ports ensure minimum flow noise.