The S18E-AD is a high output Infra™ subwoofer system designed to provide high fidelity extended low frequency audio reproduction from a relatively small enclosure. The S18E-AD provides perfectly flat response down to 8 hertz when used in conjunction with the 8 hertz Integrator. Our external rack mount Infra-MXB Integrator is recommended to drive a line level Infra™ processed signal to the amplifiers driving one or more S18E-AD systems. Designed for portable use, the S18E-AD offers a black Ro Tex™ finish and a black coated steel grille.