Comprising of two X-Lite 12A loudspeakers and two X-Lite 18SA subwoofers, the FBT 4000 is a complete PA speaker system. The FBT X-Lite 12A is equipped with two amplifiers, one Class D amplifier that handles the low frequencies and one Class AB amplifier that processes the high frequencies. The combined dynamic range can reach an impressive 127dB without any distortion, and sounds great even at the loudest volumes. The FBT X-Lite 18SA is a 1200w processed active subwoofer that has a frequency response ranging from 38Hz – 120Hz.