Speaker operates on a frequency bandwidth of 65Hz to 20kHz. This response can be lowered to 32Hz with the addition of the SB18 subwoofer. It contains a 1.5-inch diaphragm compression driver coaxially-loaded by an 8-inch low frequency transducer mounted in a bass-reflex tuned enclosure. The internal passive crossover network uses proprietary third order filters. The linearization and protection of the transducers is defined by the drive parameters contained in the amplified controllers.