Cardioid bass speaker. This innovative sub-bass unit offers a distinctive, dual-transducer configuration using one 18'' woofer in a ported reflex configuration, and a second, 15'' woofer loaded by a folded horn. The two transducers are purpose-built for the RAB1815. They are constructed with neodymium magnets and 4 '' voice coils, and can boast an excursion of ±23 mm. Features frequency response of 30 Hz - 120 Hz, maximum SPL 136 dB and the power of 1600 W at 4 ohm in both woofers. Dimensions: 51 x 76 x 75 cm. Weight: 58 kg.