Martin Audio Bass, a vented sub-bass system offers a frequency response of 40Hz-120Hz ± 3dB. It features an 18″ (460mm) bass driver and has a rated power of 500W AES, with a peak power handling of 2000W. It is recommended to use an amplifier with an output of 400-1000W into 4 ohms. The sensitivity is 99dB, and the maximum SPL is 124dB continuous and 130dB peak. The nominal impedance is 8 ohms. The subwoofer has a 120Hz active/passive crossover. The enclosure is made of 150-liter multi-laminate birch ply and is finished with textured black paint. It is equipped with a black perforated steel protective grille. The connectors are 2 x Neutrik NL4. The subwoofer has a top hat fitting for mounting purposes. Its dimensions are (W) 561mm x (H) 690mm x (D) 595mm or (W) 22.1ins x (H) 27.2ins x (D) 23.4ins. The weight of the subwoofer is 45kg (99 lbs).