The ETX-18SP is a powered 18″ subwoofer for the ETX range of PA speakers, a versatile choice for live entertainment venues, rental companies, pro musicians and DJs, and installed sound. The low-profile, tour-grade wood enclosure hosts a transducer and a Class-D amplifier. Signal Synchronized Transducers (SST) waveguide design and smart FIR-Drive DSP work together to provide precise coverage at the highest SPLs. 18″ DVX woofer for extended low-frequency response 1800W Class-D power amplifier with integrated FIR-Drive DSP 135 dB peak SPL DSP preset for a true cardioid performance across the full operating bandwidth Combo pole cup (insert and threaded) for use with the ETX Powered Loudspeaker full range models Removable casters